Here is a great recent thread about how to get things, as well as other helpful advice: (see my post #8 and other's posts on getting packages)
Hey guys! I'm a doolie and with your basic coming up, I wanted to share some advice. 1) First of all, basic training feels like it never ends but you gotta remember that it is only a really small part of your academy experience. So embrace the suck and remember that it will end. You're going...
www.serviceacademyforums.com
You could also have your parents make friends with parents group and often they will bring things up for other Cadets. We always offer my parents group BFF to take packages up when we are going to COS.
To directly answer your question: I don't recommend a storage unit. While possible, it's not practical. If PW is cancelled and/or parents don't come, or you can't see them - it's going to be something like Wing-wide pandemic posture, you are in Q&I, or you are on some probation and denied the privilege of leaving base. So that defeats the purpose of having things in COS when you can't access them anyway. Plus as
@Capt MJ says, you don't know what you'll need, be allowed, and what fits, especially if you get a 3-man unbunked room.
For parents: it helps to have a mindset that you will know everything last minute. As in, well past the time to get cheap airfare, ideal accommodations, etc. You have to plan ahead and often guess, perhaps with fully refundable tickets. I suspect it will still look more like 2024 rather than the known, plan-able, pre-Covid it's-always-been-on-xyz-schedule. Don't assume your priorities are USAFA's - theirs is probably focused on graduating the class of 2021. So no, we do not know DD's finals schedule, whether she's allowed some leave before 1st block, and thus also not for how long, travel radius, overnight...nothing. It doesn't bother me. After getting a glimpse of the comprehensive planning, I can understand why they try to avoid half-baked instructions. DD was in the unfortunate Q&I group in December and lost a week of winter break. She was accidentally included on a premature email saying she would be allowed to come back later, but they were in the process of getting EVERY teacher to ok this. That took awhile, and when the official email came, it was about 3 days before regular reporting time. So we appreciate they didn't just throw out a half-baked idea and then leave it to the Cadet to deal with it, they provided a comprehensive return schedule based on how long each had been in Q&I plus every teacher was on board with it. (DD chose to come back at her regular time, she was in a virtual triathlon sprint for bed/desk position with her 2 new roommates, finally agreeing that it was every man for himself/first come first served; she said she got the 2nd best positions, whatever that is).