don't worry about camo, at airsoft ranges block colours work just as well anyway, as long as you're not wearing bright orange you're all good.
chest rig/plate carrier etc wise, budget and capacity are your two main factors here; with a molle rig you can tailor it 100% to your requirements or theres plenty of already dressed chest rigs that are really well arranged.
Best bet is to give us an indication of how much stuff you're likely to be carrying and a rough budget, a 3x magazine and one grenade load is going to require a very different solution to 10x magazines, 2x grenades, bolt cutters, pistol, first aid kit, 3L camelbak, waterproofs etc...
Oh, and a backpack for woodland games is entirely unnecessary, never ever have I had a requirement for one on a standard walk-on day.