There IS a lot to do as far as college applications go. Bopper gave you excellent advice, especially doing the research about level of interest and interview requirements. Everything you can get out of the way over the summer will benefit you during the school year.
Having said that, you need to find a good fit, a vibe that matches yours. The best way to do that (after accounting for affordability, majors/areas of interest, etc.) is by doing the same things - to the best of your abilities - you’d do if you were trying to “demonstrate interest”. If you don’t have time to get to know the colleges, it may be better to cull your list a little.
Of course, it is possible to visit after you are accepted and attend admitted student events. However, we’ve seen a lot of kids on CC shut out of their reaches, then their safeties didn’t take them either because they didn’t show enough interest. The college didn’t think they’d attend, so they sent a rejection letter to protect their yield. “Love thy safety” and show them some love!