Reckon a TDM900 is worth test riding. I bought new a 1st-gen 1992 TDM850 and quite liked it. Over the revisions they just got better and betterer (at least on paper).
I really liked the stonking motor, super comfortable seat/ergos, sharp brakes and great long-travel fully-adjustable suspension. There were two big gotchas for me at the time: poor wind protection so very cold riding for hours at night, and too top heavy for off-road work. 30,000km in a year and I sold it because I was doing too many highway miles so got a Trophy 900 which was way warmer so much less tiring. I should have got the Tiger 900 as it had everything the TDM had, plus good wind protection, but I was scared off that class of bike by then. Several years later I had both the Trophy AND a Tiger.
It really was a hooligan go-anywhere bike. Seemed to soak up everything I threw at it on rough gravel roads. Commuting around Sydney, I knew lots of places where I could get it airborne, and did so habitually... which nearly bit me in the bum when I changed to the Trophy
. It would snap your arms out of their sockets changing up to 5th above 200km/h. Smoky 3rd gear burnouts on the dirt. Hmmm, rallies have a lot to answer for, eh?
Swapped out the twin 35/35W headlight globes for a pair of more typical 55/60 watters, and wow! more light than I ever needed. Have seen plenty with hard luggage fitted, and knobblies if you want to go there. Oh, one drawback with the power delivery: at 2800-2900 rpm the power cut in like a two stroke 125 MXer hitting band. That meant on loose dirt it would spin up, on firm rock it would wheelie. Not a lot of fun when picking your way up a really snotty 4wd track. Great fun when short-shifting up to 5th on a straight gravel road
Had a pretty lousy touring range although probably better than a sportsbike. The tank looked big but it was a thin pancake wrapped around the battery (and airbox?). That's one thing that improved throughout the years.
No doubt I wouldn't be so impressed with the engine or the suspension these days, but I guess I'm saying: try it, you may like it.
If you really want bump compliance you need long travel suspension. Although almost any road bike will handle occasional gravel roads no problemo, bumpy backroads (and state highways!!) need something more than even well-fettled road suspension. DAMHIK. Adventure bikes like Trannies & Tigers just cope better. They also have a broader spread of power. An "885" efi Tiger 1999-2000 might do you well, too. I can't recommend any of the 900-badged bikes, they had a few foibles which impacted their durability.