Is this the green one that was on eBay in Cheltenham? If so, it’s a Tange midsize/prestige mix of tubing and is the 1997 model; my dad had one and it was a lovely bike. came with a full deore lx groupset apart from the hubs which were STX RC. Also had ritchey bar and stem with mavic 217 rims...
I have a few early Marin’s; on my 94 I run a 70mm marzocchi bomber and it feels great and not too long; for a 92 though I would say max 50-60mm travel; as someone above said an old rock shox judy or quadra would be just the ticket