My neighbour would like his window trims, 3 doors and 3 garage doors painted in an oil base. He is willing to pay the "going rate" and I could use the extra $$. What is fare in pricing? By sq ft or time?

Going rate for what, a painter or a handyman. You can't expect to get what a painter gets so just figure what your time is worth, go by the hour and see if he agrees.

I used to paint, so I can vouch for an hourly time. I never suggest using oil base if I did not have to. That used to be "the way", but now there is a very good exterior acrylic.

No matter what, you need to consider prep time: Scraping, sanding and any repair, including caulkng. I used to do a light, medium, to extensive rate on prep. Also add for priming if needed.

If the existing surface is badly peeling, then count on extensive prep time. You will need to scrap, sand and prime then. People do not understand what primer does. It helps bond the coat of paint (as well as aids in color change) "spot" priming may be necessary.

When you don't know how long, best to work out this by hourly. If you are new to the work, it will take you longer. You can have him get the materials for you as well and lower the hourly rate somewhat.