Borrowing is good!
Perhaps the most important advice is to try everything out before you go. Practice setting up and lighting the stove (on your own stovetop, for safety), set up the tent and rainfly and sit around in it for a bit, unpack the sleeping bag, pad, and anything else so you're sure you know how to set it up and to re-pack it. The last thing you want is to do is to have to figure this stuff out in the dark, in the wind, in the rain, or when you're completely pooped.
That goes for food, too. If you go with freeze-dried or other pre-made food, buy a couple of brands and make them at home to see which ones you like. If you're making your own, make a list of ingredients and make sure the stuff will keep in your pack. Never underestimate the beneficial effect of tea or coffee or hot cocoa in the morning. One of my tricks was to bring pasta and one of those packets of sauce you can get at the store (again, try at home first), or a film canister of tomato paste and little plastic pill bottles of dried onion and spices for pasta and sauce the first night out.
If I were being conservative I'd say car camp for a night or two; then a one nighter with a short hike in (so you have plenty of time and energy to set up camp); then a weekend. Once you have that down, getting ready means gathering your gear, packing food, and filling water bottles. Longer trip = more food (and maybe an extra book); that's about it.
It's really nice once you've got your routine down for packing, setting up and breaking down camp. When I was a frequent backpacker, most of my gear lived in my pack, so all I needed to do was add my jackknife, water bottles and clothes and pack my food. Any trip over two days involved some amount of home-made whole wheat banana or poppyseed bread.
I'd bring treats, too: a water bottle filled with frozen fruit juice for the first morning, a chunk of dry salami (well wrapped), junk-food beef jerky sticks. Fingerfuls of peanut butter dipped in a bag of granola provided many a happy lunch for me. Many of my buddies always brought fresh veggies, and I'd humor them if we camped together, but generally I didn't care much.
Without going into details, I like 2 person tents (without the men), 20 degree sleeping bags (two in cold weather), and when I wasn't so creaky I used a 'corrugated' foam pad which was super-light, versatile and bombproof.