Welcome to the forum. We looked at the Thompson 44 before buying our Cheoy Lee, and thought it was a very nice boat. The example we looked at needed a little too much work for its price, though.
I found little in the way of factory info on that boat, as some were made hull, deck, and power at the maker, and finished by the owner or another yard. You should be able to get manuals for the engines, trans, and other major systems.
Books like Calder's Boatowners Mechanical And Electrical Manual will be a great help as you figure out what previous owners have done, and try to figure out why ;-)
Where are you based, and what are your cruising plans?
Any pictures of the boat yet?
Cheoy Lee 40 LRC