If the map (reading) light bulb is burned out in my own Cessna 210, what are my options if I want to fly FAR Part 91 under night-time VFR?
As the owner, you (likely) may replace the bulb yourself
It comes down to the complexity of the work.
Owners can now do far more preventive maintenance than the 32 listed items
For many years, the FAA treated the 32-item list in 14 CFR Appendix A to Part 43 as exhaustive. The interpretation was that if an item or procedure did not appear in section (c), then it was not preventive maintenance. Case closed
However, in 2009 the Coleal Legal Interpretation, produced by the FAA's Office of Chief Counsel, superseded the prior rules. It specifically calls out and contradicts the understanding that the 32-item list is exhaustive.

Even though the introductory text of subparagraph (c) states that “[p]reventive maintenance is limited to the following work ....” (emphasis added), in view of the broader definition of preventive maintenance in section 1.1, we believe that such limitation is not controlling. Similarly, for the same reason, we also believe that the following sentence in Advisory Circular 43-12A … is overly restrictive. That sentence, found in Paragraph 3(b)(1), states: “If a task or maintenance function does not appear in the list, it is not preventive maintenance.” As with the other paragraphs of Appendix A (i.e., on major repairs and major alterations), the lists are better viewed as examples of the tasks in each category – they cannot be considered all-inclusive. There are, no doubt, many “simple or minor preservation operations [tasks]” and many “replacement[s] of small standard parts not involving complex assembly operations” performed daily, especially on small general aviation aircraft that the agency would consider to be preventive maintenance, though they are not included in the 32 listed items. It is our understanding that Flight Standards' Aircraft Maintenance Division is planning to clarify this issue in a future revision to the AC.

In short, the list of 32 items is not exhaustive.
Is the map light preventive maintenance?
So we know that there is preventive maintenance which can be done which does not fall on the list. However, this does not imply that all maintenance is preventive. The specific question has to do with the map light.
Looking through 14 CFR Appendix A to Part 43, we find:

(c)(17) Replacing bulbs, reflectors, and lenses of position and landing lights.

So it is clearly within the domain to replace exterior bulbs. The question becomes whether accessing the interior map light bulb in a Cessna 210 is low complexity or high complexity.
Your A&amp;P might be able to give you some guidance, although IMHO a good yardstick is that any part designed to be IRAN'ed with nothing more than a Swiss-army knife is pretty clearly &quot;low complexity&quot; and should fall under owner preventive maintenance.