To test fitness you could go to to BBNP in February and hike the South Rim loop. I think it is around 22 miles and not bad elevation wise. I have only done in a day hike but you can backpack. Also could try a loop in the Guadalupe mountains. The climb up there is pretty extreme with a fully loaded pack since there is no water. February weather in Texas mountains can be similar to archery or early season Rifle in Colorado.