If I had any advice at all on homeschooling through highschool it would be... records, records, records. Please, keep records of anything and everything you do. It helps to be a packrat.
When I graduated, my records were spotty and a mess, so it really didn't matter if I was outrageously intelligent, no one wanted to give me financial aid! Even getting admitted was a challenge. It's definitely not like that for everyone who homeschools, but it can be for those who have little to no records. Accredidation under an umbrella school works for that purpose too.