I also dehydrate things as ingredients, it keeps things flexible. I make meals up in resealable bags when I'm deciding on the menu before I go away. I tend to use tinned veg, it's cooked under pressure so rehydrates more easily. Think Pot Noodle convenience but generally more nutritious.
Beef, I buy it as a joint when the supermarket has a half price deal and mince it myself to keep it really lean but to be honest I've just used supermarket mince and had decent results.
Ham, I use tinned. Most types are too fatty so look at the ingredients. M&S make one with 2% fat, Pek gold is also 2%. You'll need to blot a bit of fat off with paper towels as it dries but it's really very little.
Carrots, peas and sweetcorn. All tinned. I rinse them, then the corn and peas go straight into the dehydrator. I chop the carrots into small cubes so they'll rehydrate easily. It's possible you could use fresh veg and blast it in a pressure cooker but I've never tried it. I know tinned veg can be overly soft but once it's been dried and rehydrated it retains more texture and a little chewiness.
Potatoes, I just boil them, cube them and dry them.
One of my meals is very similar to one already posted. 40g beef, 50g potatoes, 5g each of carrots, peas and corn. With some herbs and black pepper added I just dump it in the pot with about 700ml of water. I bring it to the boil, simmer for a minute, stir in a gravy packet and put it into the cosy. When I feel like eating (My cosy is a double walled closed cell mat model so I've scalded myself after 45 mins) I add a sachet of mustard and sometimes mint sauce.
I add 50g of cubed ham with 20g of peas and 20g of corn to a pot of water and bring it to a boil. I add 2 packs of 'Mug Shots' cheese pasta, give it a stir and put it in the cosy. The pasta only needs a couple of minutes to rehydrate so you can eat as soon as you like. I usually add black pepper and grate some cheese over before tucking in. You can also add oil, butter or milk powder to increase the calories of course. Before I used dehydrated ham I used to make this with salami or pepperoni.
50g of ham, 50g of spud with whatever veg I feel like is good added to a pack of good soup. Not cup a soup types, the bigger packs that need simmering. Some of those are really good, the last one I had was Morrisons chunky leek and potato I think. With the added bits it makes it a filling meal.