What part of Texas are you in?i am in your same boat, a lot of stairmaster with no hands on the handlebars is great, i recently did Everest on the machine and it sucked but i feel like that is the best thing i can use to duplicate mountain hunting while not being able to actually get to mountains.
Other things that are great are obviously weighted rucks, but i carry big rocks in my hands as well, it makes it harder and simulates carrying a bow around all day. make sure you do it in the gear you are going to take hunting. I looked pretty funny wearing first lite pants and top, boots and a 40-50 lb exo walking hills with rocks in my hands in Texas in the middle of summer while people are out in shorts and running shoes, but you have to be comfortable in/with your equipment.
sandbag get ups
(If you have a big Ag tire) get two kettlebells, hold overhead, step up, into, up, over an Ag tire. put kettlebells/or rocks/case of water etc. downm, flip tire, repeat for 50-100 yards.
there are a lot of weird core strength things required in the mountains, especially when loaded with meat.