Standard hyphenation rules apply to these terms: when used as a modifier, either term must be hyphenated. When campus is used as a noun, drop the hyphen.
At UA, on-campus housing is plentiful and convenient. Students who live on campus also find it affordable. That building is located just off campus on Queen City Ave.
Don't use "off of," use just "off."
Capitalize office only when it is part of an official name:
Registrar's OfficeBusiness Office
Numbers used to indicate order (first, second, 10th, 25th, etc.). Spell out first through ninth: fourth grade, first base. Use figures starting with 10th.