It seems like the idea of "taking a gap year" is growing in popularity among homeschoolers.  A gap year is a period of time (usually between 6 months and a year in length) where the high school graduate takes a job or does some volunteer work to gain experience before beginning their college career.  

Gap Year policies vary WIDELY between colleges.  Some colleges say if you take one, you may be considered a transfer. Other colleges (including Ivy League colleges) will admit you, give you great scholarships, ENCOURAGE you to take a gap year, and STILL allow you to have your scholarships and freshman status when you return!  Unfortunately, any specific advice I give on this subject will be incomplete.  Your best bet it to contact three or four colleges that your child would MOST like to go to, and ask them specifically about their gap year information.  Remember too that their policies can change from year to year.  Also, be careful to get assurance that the policy they quote you is "grandfathered" and will not change if your student leaves for a year!

Even if your student is planning a year off, you will want to prepare your application and fill out the FAFSA (Free Application for Federal Student Aid) during their senior year!  If they don't apply as a senior, then they really COULD be considered a transfer student and miss out on many freshman scholarships.  So have them apply while they are still in high school.  

General advice:  fill out the applications just like any other student, with transcript, reading lists, and course descriptions.  In one of the application essays, they should focus on their gap year plans, what specifically they will do and what they hope to accomplish.  Remember the essay is COMPLETELY written by the student.  On the other hand, you as the parent can help your student brainstorm facts to include in that essay.  While your student completes the application and essay, you can call the colleges to research their policy.  Make sure you visit each college, and have your student talk face to face with someone in the admission department.  That's as good as an "interview" and can go a long way to proving they really are taking a gap year and not just goofing off.  

Yes, fill out the FAFSA.  Colleges will base their financial aid decisions on the FAFSA, and (with luck) that financial aid decision will carry over once your student returns.  You don't want your child to come back with a college admission but not be able to afford the college!

Gap year is NOT affected by "dual enrollment" college courses.  Those are college level classes taken at community college or online that are taken while the student is officially a high school student.  When they have dual enrollment credits, you put the information from the community college course onto the high school transcript, to prove that it is "dual enrollment" and NOT just a college class.  Only college classes taken AFTER high school graduation will mess up your gap year.  Your student can take anything BEFORE graduation but NOTHING after graduation (no classes during the gap year.)