Which schools are close to off-limits for transfer students?

My son has some offers from 4-year schools, but is considering doing CC and then transferring - with the intention of being able to go to a “better” school. I want him to know which schools would be big-time reaches for most every transfer student. Is there a list somewhere, or do we need to just glean this from transfer rates? Is there somewhere here to find recent transfer rates? (The lists I found seem older, and things seem to only be getting more competitive.) Thank you for any leads.

basically most schools are harder to transfer into than applying from high school, but top schools such as Harvard, Yale, Princeton, MIT, Stanford, top LACs, and a few others are next to impossible to transfer to. Other top schools such as Cornell, Hopkins, Northwestern, Duke, Wash U, and Georgetown do have a number of transfers, but it is still a reach for all students.
The most transfer friendly schools from the top 30 are probably Vanderbilt and USC. Public schools (UVA, UNC, UCLA, William and Mary, and UMich) are also transfer friendly to CC kids from their state.

Some of the contract colleges of Cornell are also transfer friendly with some NYS schools and CC’s they have articulation agreements with.

Go to a California community college and then try to transfer into UC schools, all UC schools are transfer friendly, six of them gives guaranteed transfer under condition, the other two, UCLA and Berkeley gives California community college students priority in the transfer admission process

Princeton currently admits no transfer students, but will do so in a few years as part of an expansion. It looks like the motivation is to enroll more non-traditional students, those from low income backgrounds, and athletes.
https://www.insidehighered.com/news/2016/02/03/princeton-university-will-resume-transfer-admissions-first-time-1990

The military service academies do not admit transfer students, but those with post-high-school college credit may apply as frosh if they are otherwise eligible.