Sure this answer may be in the database somewhere... but what the heck...

What tools/pumps work best for pulling oil out of the dipstick opening? That seems to be the most accessible place for me.

I used a small handpump on a friend's boat... and it was a royal PITA. (wish I remembered the brand, of what NOT to get) The thing required that we draw back and hold the "pump" handle until it filled the chamber and then we pushed the plunger in to pump the used oil out into a container. The pump was "mickymouse" and did not retain the hoses well, and the action was terribly slow. The whole arrangement looked like a syringe with a small 1/8 inch tube intake and a 1/4 tube output; the whole thing was about 12 inches long or so, with a T handle.

There has to be a better way... or better tool.

My access IS somewhat limited. I cannot for instance "walk into" my engine room... as no doubt some of you can. So probably the best access is via the dipstick hole.