What are some ways in which homeschoolers can transition to regular school?

There are many bridge programs to introduce homeschool students to classrooms. All university campuses have summer bridge programs where students can take college classes. If you have over 3.0, you can attend classes at the university level with other college students. Besides this, local colleges may have a writing grammar workshop and a science workshop geared towards high school students. Homeschoolers can attend high school classes there. The grad school students teach there to get their teaching hours in and work with a small group. So the students get the experience of a classroom and socialize with peers.