Some options up north in Nebraska:
Hebron/Thayer Central on Friday is mostly Class D schools and Osborne, KS. 1 or 2 solid teams, mostly all over the place for the others. deb.vorderstrasse@thayercentral.net is the contact person.
This wouldn't be a bad haul for you all at about 2.5 hours.
David City has 2 different dates. 1 on Friday has a lot of class C schools (comparable to 3a)...and some very good ones at that. Saturday has mostly B schools (mix of upper tier 3a and mid tier 4a on this).
Louisville invite (just outside of Lincoln) has a mix of B, C, and D teams, plus West Harrison High out of Iowa this year. Looks like you can bring entire team to that as one has 36 entries.