I wonder if your son would be interested in a trade education. Cal Maritime Academy is a Cal State University and its engineer careers put the kids under some academic training but mostly it is hands-on. It is a small campus and they have strict rules of conduct because they prepare the kids for jobs that entail safety and security of systems, ships, and logistics. And their graduates get very well paid jobs soon after graduation. Take a tour and find out more about it. It's a great school and it's nearby.
My son was exactly like yours, not overtly smart but definitely with the brains if he applied himself. But he was scattered and uninterested in anything academic. He was a B-C kind of kid and boasted that he rarely studied during high school and definitely did not spend real time for homework or projects in his high school years. Fortunately for him he chose and got accepted to Cal Maritime. He had some hiccups with his academics but he did graduate last year, is now well employed and loves his job.
For my son community college would have been a black hole because he was not focused and was not ready to navigate what is basically an independent study. In my opinion to succeed in a community college you have to know what you want, stay focused and find friends who have similar goals as yours. Knowing my son we believed he would have associated with kids that were not academically inclined. Cal Maritime provided a focused environment, only 5 careers to choose from, not the sea of options and set courses that were determined buy your choice of career path. For my son that worked great.
I agree with you that freshmen year is important. Lifelong friendships are formed then, and the students get a sense of living 'independently' away from home. Both my kids loved those first years as they started the process of separation. Whichever choice you/him make, my suggestion is make sure he has all the required courses to apply to a 4 year college, and apply. You can always decide last minute to go the community college route. Also, if he ends up going to a 4 year college, monitor his academics closely. Get him to authorize you to access all his records immediately after starting school. Will be glad to discuss more personally if you are interested. Much luck.