I used to be pretty confident with myself to 500 yards. Then I bought 65 acres and setup a 500-yard steel plate range and 50-yard rimfire range. My trigger time increased tremendously but instead of scheduling shooting days around cooperative weather and enjoying accuracy under ideal conditions, I found myself frequently shooting in all conditions and being humbled pretty regularly. I wanted to believe it was related to my kit - I went through every long gun which consists of everything from off the rack budget guns to a full-custom 30-06. I ensured everything was properly torqued, loc-tited and all things I could control. It was me, not my guns.
Reading here and elsewhere and picking up training tips that I've employed (with my son as well) my consistency has improved quite a bit.
To your inquiry OP, in my experience there's no better alternative to getting better at 200 yard + field shooting than actually engaging in 200 yard + field shooting. Dry fire, rimfire, practicing getting into different body positions, practicing setting up with your pack and/or some kind of rear rest etc. are all important exercises and also really helpful, but ultimately, you're going to have to put together day trips, overnighters or settle up with yourself and scout out a good public land spot.
Despite having access to what I have at home, my son and I still venture out into the public lands to practice weird contorted shooting, practice screwing around with my ballistic app under time constraints (as if we had a legal animal spotted), dealing with angles or crappy rests, wind, rain, heat, shadows, being hungry and more. We love it, it's fun.
The result was my 10-year-old son taking his first buck a month ago from a kneeling position with his rifle setup on stump, sitting through a heavy coastal squall only to have the buck appear to our left and he twisted his upper body and drilled his buck with an offhand kneeling shot. It was second nature, and he was able to quickly and calmly follow my instructions in the heat of the moment.
Give me a 65-degree day, calm wind, clear & dry conditions and I can hit my 500-yard plate 10/10 times sub moa. When I setup and it's 30 degrees out, gusty winds, sprinkling/raining/snow or fog/mist I'm happy if I hit my 5" 300-yard plate 75%.
I get the whole anxiety about safety concerns or other public land users possibly taking issue with your pursuits; however, that's part of the drill. You still have to exercise caution about what's behind your target when you're hunting, you still have to be aware of hunters and non-hunters alike when you're hunting, you still have to scout out hunting zones - you can do all those things during the off-season too. The only difference is that you're shooting at paper or rocks or whatnot. The biggest concern should be your fuel expense and ammo bill
