Loosing weight: I'll mention getting in hiking shape in a bit...
Here is a diet that I liked a LOT since you can eat a lot (of the right stuff). It is designed to give you a bit more protein, a lot less fat and a bit fewer carbohydrates.
I'll locate a link to the plan, but the basics are 6-8 equal sized (calorie) meals a day. Nothing white (bread, pasta, sugar, ice cream, etc), no alcohol (wine, beer, etc). Go on line to determine your expected daily calories requirements based upon your current weight. Add 10%. You are not to eat more than that over those 6-8 meals a day. It will get adjusted as you get better at throwing your weight around. You have to eat enough to complete your workout plan.
By the way, the body's way of getting rid of fat is to use it up as energy (a sugar) spent moving muscles around and letting you exhale the by products: CO2 and H2O. This goes on while you sleep too. Another reason to breath often.
Get used to drinking a LOT of water throughout the day. Your body is a manufacturing plant and has to flush out a lot of debris. Plain water is better than a fancy expensive one.
A typical meal could be:
1/4 pound deli beef sandwich, NO mayonnaise, lots of mustard if you like it, a slice of tomato, and slice of onion, lettuce. Diet coke if you like 'em, otherwise 0 carbs from liquids. Two thin slices of a pumpernickel bread.
4-6 egg (whites), mushrooms, basil, fat free cheese, fat free milk (lots of sugars but also loads of protein). Two slices of bread/toast.
Get the idea? Lots of protein, some vegges every meal a little carbohydrate, no added fat. AND a one serving of a multivitamin.
I try to consume a gram of protein for every 2 pounds of my weight per day.
I like a protein drink (like Muscle Milk - chocolate) it has 16g protein per scoop) for breakfast that has 1/2 cup milk, banana, apple (entire thing including seeds/stem), carrot, Brussels sprouts, parsnips, cabbage, hand full of frozen berries...etc. or whatever is handy or available). I add ice to the drink - free calorie. I do two of those a day - usually breakfast mid afternoon.
The strategy is to make your body not catch on it is being starved. This diet gives you enough calories/energy to do a fairly aggressive workout everyday except for (pick a day). This is a weight lifter's diet. The fastest and best way to loose weight is to make sure you have enough energy to complete your work outs. If not - eat more.
If you are tired, up the carbohydrates each meal a bit. If your workout clothes smell of ammonia cut down on the protein a bit.
This is what you are trying to do
You want to add muscle by using weights at a gym. Get a personal trainer to give you a couple of days to start with on how to use the equipment. Then think of maybe once a week or so with her/him. Don't go into free weights for several months. Sooo ... you energize the BIG muscles by using up fat reserves for fuel. You add a little more muscle every time building it by replacing energy from eating.
General rule is (while loosing weight) that if you have enough energy left over to do aerobics, then skip the aerobic exercise and put more effort into lifting and moving machine weights. Controlled weight lifting or moving is so much more efficient in loosing weight than a walk/jog/run.
All the muscles below the belly button are your largest muscles and will consume the most energy/fat while being worked on. The upper muscles (above the belly button) are smaller except for a few in the arms and back. Work on those especially on MWFS for an hour a day. Give those muscles a rest and do upper body exercise T,Th. Again work on the bigger muscles they more efficiently convert fat to muscle.
Have the trainer instruct you in strengthening your back and abdominal they should be part of your warm up. The key is not to do more of one without doing the same amount of work on the other. You can do ab exercises for hours and never loose a pound. Its the big muscles you want to work on.
After a couple of weeks at the gym, add a nice walk/short hike every day.
When you have a definite downward slant on that weight loss graph that you put on the fridge and you have lost about 20 (of the 60) in the gym, its time to start doing aerobics and making the legs go. At 60 pounds you had too much weight to start out jogging.
www.exrx.net/ is a go-to resource on the web. Look at the jog/walk program on the Beginners page. Following it (after loosing weight) will help keep you from getting hurt You can do this on a treadmill where it is warm.
Warm up on a non impact, but repetitive machine for 10 minutes or longer to get started on perspiring. Don't shock your body by starting on anything intensive until at least the oil is warmed up.
You will shortly find that it is difficult to eat 6 equal meals a day - it is a lot of food.
Get ear buds and something to listen too. This is really REALLY boring stuff.
Hiking stuff.
Find a long set of stairs (several floors) and start out for 15 minutes at a medium pace. After 10 minutes adjust your pace so that you inhale on the right (or left) foot and exhale on the other foot when it hits a step. Now make this pace fast enough (still step breathing) so that you are uncomfortable but can keep the pace going for 2o minutes. Stop and take you pulse and get a feeling about how uncomfortable your breathing is.
The goal is to maintain a consistent manageable heart and breathing rate by changing the length of your stride. Make your steps a little closer up hill and farther apart on level or down hill. You want to find a rate that you can keep up for an hour. You can use a stair stepper or similar in the gym to figure out YOUR pace. This is the most efficient way you can lug a pack anyplace.
If you see a hill or incline coming up, start step-breathing early on. It takes 20-30 secs for the body to tell you to start breathing harder. Oxygen deprivation is tough to make up.
Trails are complex. You don't put a foot ahead of another like you do on a street. Don't do any of these with a heavy pack on.
Imagine a straight line ahead of you, and place your right foot to the left of the line, then bring your left foot forward just barely clipping your heel of your right foot and plant it just to the right of the line. Continue until you get bored or too tired to continue.
Bring your right foot forward and plant it to the right about a foot off center. Bring the left foot forward again clipping (almost) your right foot and plant it forward and to the left a foot. Work on moving the plants farther and farther out. Its sort of like ice skating.
These two exercises strengthen tendons and muscles that support your knee and hip.
Trek poles - get two. Place about 10-20 pounds of weight on the pole as you step ahead of the pole. The nylon loop thingy goes under your wrist. This allows you to take about 20-40,000 pounds off your legs and transfer it directly to your skeleton - per mile. No muscle involved. This assumes you have 1000 strides per leg per mile (a mila). 2000 strides times 20 pounds = 40,000#). Your arm weighs about 5.3% of your body weight. So just taking the weight of your arms off your feet is worth something.
Hiking, once you are in some manner of shape is mostly aerobic.