As the owner of a Bahama 30 for the past 12 years, I may be able to help with some of your questions.
Could the water you're seeing be coming from the forward opening ports or the hatch? When we first got our boat, I believe it had the original opening ports and they leaked badly. We replaced them with Lewmars and have had no problem since. The hatch isn't a particularly watertight design, and needs good weatherstripping or similar to stay (semi-) watertight.
I'm aware of the compression post problem on the B30, but ours is fine. Our boat is a 1980, and perhaps the factory corrected the issue by then - I know that they became aware of it at some point. I'd certainly monitor it.
We keep our upper shrouds quite tight, and the lowers a bit less tight. The main thing is to keep the mast in column when heeled over in a breeze.
We haven't added any storage space, but there's a lot a space under the starboard settee for food stores, and storage for large items in the port seat locker. Our family of 4 has gone on several week-long trips on the boat. We bring so much gear, food and junk that the waterline goes down by a few inches, but we always have plenty of space - we use the quarterberth for personal gear.
My best tip for engine access is to become a contortionist
. Do you have an access hatch in your quarterberth? Between this hatch and the forward end access you can get at pretty much anything, but it's not easy.
We have a 6 gallon rectangular water heater mounted under the forward end of the quarterberth, near the batteries. We don't have the engine water plumbing hooked to it, so it only operates on 120VAC. We found that with the raw water cooling system (assuming you still have the original Volvo), the saltwater gums up the guts of a water heater pretty quickly.
We have the bottom cleaned monthly here in So. Cal, where things grow pretty quickly, and haul the boat out for bottom painting every 3 or 4 years. As far as maintenance, we just change the oil & filter every 50 hours (again, assuming you have the Volvo - other engines might have a different interval). Fuel filters need to be changed occasionally, although we don't have a regular schedule for those. Incidentally, I'd recommend adding a secondary fuel filter/water separator such as a Racor if you don't already have one. Also, keep on eye on the water pump impeller and always have a spare on hand.
We have a dodger that we keep on at all times, and it's pretty nice when conditions gets rough - a lot of spray gets back to the cockpit. We don't have a windlass. It would be nice, particularly if you do a lot of anchoring, but they are a big draw on the batteries.
Enjoy your boat! We've had a lot of fun with ours.