Community colleges aren't really the place to find biology, though. There are few (if any) disciplines where laboratory-grade biology knowledge can be applied without the kind of background a bachelor's degree would confer. You're more likely to find people who are both useful and open-minded around full-fledged universities.
I agree a community college is an unlikely environment to find someone who will understand your desire to tinker nor will you be exposed to cutting-edge science or be trained as a scientist would.
Community colleges DO teach decent lab courses in molecular biology (i.e. e.coli manipulation) which would give you most of the skills you are looking for. Pretty much every community college offers such a course as there is a high demand for qualified lab technicians. It would be a stand-alone, hands-on course with few (if any) prerequisites, which your 10-year old bachelors degree probably satisfies. At my local CC, for example, they teach this course:
BIOL 285 - Molecular Laboratory Tech
This course is an introduction to the principles, concepts, and analytical methods of molecular laboratory techniques. Laboratory studies are conducted on the molecular level, and genetic engineering (recombinant DNA) is utilized in several laboratories. This course is recommended for students planning careers in biology, biotechnology, or advanced professional health. Offered Spring. A lab fee will be required.
3.000 Credit hours 1.000 Lecture hours 4.000 Lab hours
Additional points to consider:
1) At a 4-year college, the official answer is usually "no" to any request from a non-student, because they selfishly want you to pay $$$ for their continuing education or adult night school. If you ask a professor personally, however, they might be cool with you sitting in on a large lecture course, but not a lab course since those resources are strictly for degree seeking students. But never ask through official channels, the official answer will always say "no".
2) Departmental seminars, however, are usually open to the public, you can safely attend those without asking for permission. Universities often have special seminars by notable scientists aimed at the general public which are much more accessible, check the event calendars.
3) At a CC, you don't need to enroll in a degree program just to take one random course for your own self interest, nor will anyone care/notice that you aren't 18. Enrolling in a course is the best, most efficient way to get hands on training, perhaps after some self study with a good primer on molecular biology.
4) You can likely afford the cost of a CC course, which will be ~100-150$ per credit hour for residents , whereas at my university part-time enrollment costs 1,200$ a credit hour!!!
5) Home brew workarounds will make much more sense once you see how things are "normally" done with proper equipment. Actually, a poorer school will likely have the same old, beat-up equipment that homebrew folks pick up on ebay, so you might actually learn more applicable skills than if you trained with a cutting-edge setup.
I second the biobricks recommendation. When I become a prof I will definitely start an iGEM team and contribute some biobricks.