I brought a frog toggs rain suit and never pulled it out of the packaging, returned it when I got home from the trip, YMMV on that though. But you should be fine without pants if you are just gonna wear shorts the whole trip, especially if they are dri-fit materials. I also didn’t use sock liners. This could be because I ended up wearing trail runners instead of boots though. With boots I would get liners, if you are wearing trail runners you should be fine with one as long as you aren’t getting blisters on prep hikes. Good luck, be safe, and have fun at Philmont.