Just about any resort/condo you stay at will have a dive package with somebody. Most also have one that includes the truck. Some even add in the insurance.
As laurel said, at GRI you'll want a truck. They're a little too far to walk to the water - with gear. They're just east of the rotary but the diveops in that area are all perpendicular to the water (except Sand $) so it's quite a walk to the ocean - no beach there as it's all ironshore. And you're also a few minutes north of town, most of the affordable restaurants, the bigger foodstores etc. Although there is a little market just past the rotary also. And the Lover's Ice cream store. Not a lot of cabs on Bonaire either and no other public transportation - it's just too small.
Most of the orientations are done in the morning. At the smaller resorts you might be able to get a personalized one on your schedule. One of the best was BD&A's, their naturalist gave it. I was doing an SI so sat through about 20mins. of it, it was a lot better than ours had been. But you'll probably kill the better part of your first morning doing it and your checkout dive. So if there's an 11:00 or 1:00 boat you could be on those.
If you plan to dive the piers, I'd set that up before you go. There's a limited number of slots and almost all the diveops do them. If a boat is loading at Salt Pier, you won't be able to dive there.
I'd add Witches Hut to the list of north dives that were an easier entry. You can also park close to the water there. 1000 Steps is 64 rock steps down to the water. It's easy going down...lol.
You might do a day north and a day south. Good south sites with easier entries are Bachelors Beach, Angel City, Alice In Wonderland or Invisibles (just past Salt Pier)
Anything farther south is going to be (mostly) advanced diving. From White Slave to the Lighthouse. In the afternoon you may be the only ones in the area also - we were more than once. So heed the warnings about windows down (coral rubble breaks them nicely) and not leaving anything of value in your truck. (except tanks)