We looked at some Passports when we were shopping. If I recall correctly, the Passport 42 and the Slocum 43 had the same hull, so you might find additional information by going that route. All the different boats we looked at kind of run together now in my head, but you might want to check whether they used coring in the hull below the waterline. I think that was a concern of ours when we were looking at a Slocum 43.
The P42 and the S43 are the same boat out of different yards. We nearly bought one a couple of years back but decided against it due to the cost of restoration. Also known as the Solar 42.
I don't think they had cored hulls though they did have cored decks. Generally speaking built like the proverbial brick outhouse but critical factors are teak decks and tanks. Nothing inherently wrong with either until you come to replacing them. Getting the fuel tanks out can be done by dismantling the cockpit locker but the forward mounted holding tank is another thing altogether. If there are any original deck fittings and seacocks then you will probably want to replace those as well. I did have an original brochure for the Solar 42. If the OP is interested then message me and I'll email it to you.
While we were slightly disappointed that we didn't end up owning one at the time, since then I confess to having become a bit more performance oriented and now don't regret our decision. Although I am a great admirer of other people's canoe sterns/double enders whatever you wish to call them, my preference is most definitely towards a transom stern.
btw...the Tayana 42 was designed by Robert Harris not Stan Huntingford and to my mind is the superior boat as is the Bob Perry designed Valiant. Perry once remarked that while SH did some nice boats there was nothing he ever did that someone else hadn't already done better (or words to that effect). Bit harsh but probably true.
Decks btw were cored not with timber but some kind of rubber/plastic material. On the one we were looking at there was absolutely no degradation of the core whatsoever despite some pretty dodgey installation of various bits of deck hardware.
Tanks (see above).
Fuel (under cockpit) iron x two. Get in underneath them. You will be able to get your hand under the tanks if you empty the lazarette and remove the panel. That is where you will find the rust if it is not apparent elsewhere. If the tanks are original they will need replacing.
Water and Holding. Stainless but of questionable quality. Water tanks seemed OK but the holding tank was completely shot and would be a nightmare to remove. Shower drains into bilge which is far from ideal but once the HT is out you can get a grey water tank in under before you reinstall new HT.
Ballast...iron. On ours there was no indication of any degredation. Plenty of it btw, they are a stiff boat.
Performance...for something as big and heavy as they are and with a relatively small sail plan they sail surprisingly well. Owners I have spoken with swear by them in anything over 20 knots, they get by under 20 but expect to do a lot of motoring under 10. They are best with the sheets eased. Close winded they are not. Fin keel with skeg rudder means they don't much like steering in reverse but thats to be expected I guess.
Reputation re repairs and maintenance is going to be dependent on the individual boat. They did suffer from poor quality deck fittings ex factory but I doubt any of those original fittings would still be intact. Same goes with through hulls, or more specifically the seacocks themselves.
Finally, a fabulous interior. In my opinion better than any of the rivals with two very useable sleeping cabins, an excellent galley, good head with separate shower, proper sit down chart table/writing desk, oodles of storage, very comfortable saloon and the starboard quarterberth makes for a fine seaberth. Without doubt the interior is the boats best feature, other than the bullet proof construction. The cockpit less so. Not sure why but I never really took to it.
Memory a bit hazy after all this time but any questions I can answer I'd be happy to do so.
TD