Wow, lots of good info and suggestions! I tend to overthink things so getting input from others helps me out a lot - thanks!
I am leaning more toward bringing him with me since he is my fish and my hobby and I don't think any of my family members would be willing to take care of him for the whole time I'm gone. They like watching him and don't mind occasionally looking after him when I've been gone for a couple days, but they'd probably consider it more of a hassle after a few weeks passed. On the other hand, I have a friend in the city where I'm going to school who has kept a betta before and I could leave him with her during breaks. I did think about the plywood idea but it's nice to have some confirmation on that - thanks!
I didn't think of putting him in a cup, but that's a good suggestion. I did briefly think of getting a 5 gallon, but I decided that I don't really want to downsize and I'm willing to put the work in for him to keep his space. Just because I'll be in a smaller space doesn't mean he has to. 🙂
I'm actually returning to school after taking a break to work and save up for it, so I think I'll be able to get a routine down for dedicating time to him pretty well, but that's definitely something to keep in mind. Also, I like to stay in and don't really party, so he'll definitely be used as an excuse for that, lol.