Welcome back!
Sounds like you are getting close to the maiden voyage.... Yeah, it is very convenient that the old LH-Jet gassers have that dual electric pump setup, the one in the tank is just a low-pressure booster pump that only runs about 5-6 psi IIRC, perfect as a supply pump for a diesel IP.
You could put a large-micron pre-filter down there under the floor, that's a good idea, or even just put in a piece of hose and run a line direct to the filter on the engine, or put a pre-filter inline under the hood, many ways to skin that cat. On mine I just bought some brass fitting unions and ran a line right to the motor. Somehow I have a kind of bias against putting fuel filters in hidden places now, probably dates back to an old F-250 diesel I worked on years ago that had a Banks turbo kit on it and also had an additional fuel filter that someone had installed in a crazy location hidden down underneath the brake booster covered up by a bunch of wiring harnesses... The truck ran like dog crap under load and acted just like it had a plugged fuel filter, but we replaced the filter multiple times to no avail. We banged our heads against the wall for a couple days, then finally we got down to tracing and disassembling the entire fuel supply line to look for a restriction somewhere and that's when we found the hidden second filter. Obviously nobody (including the owner) knew it was there and it had not been replaced in years, maybe ever... Changed it and the truck ran like a freight train.
Ever since then I have had a kind of fixation on always keeping all diesel fuel filters located under the hood in plain sight. However, you're talking about putting a filter in an easy-to-find place where there was already a stock filter located, and anyway you're going to be the one working on it and you'll know the filter is there regardless, so no doubt you'll be fine whichever way you go.
On the wagon I converted last year, I was able to use a regular harness connection at one of the main harness multi-connectors on the drivers side of the engine bay to power the IP and do most everything else, including starter connection, alternator, tach, etc. I think the only separate wire I ended up having to run was for the glow plug light on the dash. My vehicle was a slightly different configuration from yours (1986 740T) but originally had the same B230FT LH2.2 setup so might be similar enough. I know I wrote down what I connected to what at the time so I'll take a look at my notes and see if I can post a chart...
Unfortunately I don't have any good pictures of wiring and fuel system conversion steps but I put a selection of pictures from my swap process up in a thread here in case any prove useful to you:
http://www.d24t.com/showthread.php?t=715
Hope it turns out well, good luck and ask any questions that may come up, I went down this same road not too long ago so I might remember some answers that could save some work!