Get a hotel within walking distance.
Read everything on the championship site linked in a previous post. Looks like the 2016 info isn't up yet, but the 2015 one is still there as a reference:
http://2015.championship.usfirst.org/
Food: For breakfast, we bought a bunch of cereal, milk, fruit, etc. and ate in one of our hotel rooms since the hotel didn't have a free breakfast. For lunches, we ordered from a sandwich place that delivered them out front. Better than having pizza every day. For dinner, we walked to nearby downtown establishments. There was as welcome party the first night with free (finger)food.
Get there early enough to visit the exhibitions before the pits open. Last year we saw the arch in the morning and then the exhibitions, then the pits opened. There are some decent giveaways (swag)
Its a fair distance from the pits to the field, but manageable. Be patient.
Take time to walk around and meet teams you have gotten to know on CD.
Pay attention to special events. Last year Grant Imahara was in the pits.
There was a mentors breakfast one morning. Make sure your mentors know about that.
Have fun!