My only real nitpick with hard mode is that the only way to repair cosmetic damage is to shell out big bucks in the garage. Meanwhile, trucks will slowly lose cosmetic damage if left outside, only to regain all those dents once placed in a garage.
If you want another option for a one brand hard mode play through International has you covered, you only need the CK1500 for just a moment to drag the repair trailer to the Fleetstar. Transfer some fuel after repairing and off you go. The Scout 800 can also be quite capable so don't sleep on it. If you sell off everything else you find in Michigan (stickers make trucks more valuable for some reason) you can get the HX520 and small Paystar to have a real solid fleet of trucks even before going for the Bigger Paystar in Wisconsin.
Yeah I hate the cosmetic damage repairing. It wouldn't be so bad if the damage didn't look awful and if you didn't get random damage from tiny sticks and rocks in the road so often if you go any faster than offroad transmission's high gear. It does give me a little extra incentive to drive safely too, although I've never really been a speed demon in these games... But when I've gotta make so many trips back and forth, it's hard not to try to make up some time on the paved sections.
I save the time trial things for when my trucks get cosmetic damage. Then I can go as fast as I can for those and not worry about stones screwing up my clean truck since it's already screwed up. The first gold medal easily covers the repairs as I think it's only $2500 to fully repair the GMC/ANKs... Dunno about other trucks though, I imagine some of the big ones are more expensive.
I skipped logging stuff in my normal mode playthrough, but it's also a pain in hard mode... the logging trailers cost $14k, and it's frankly super tedious driving back and forth to fill the annoyingly large numbers of logs you need. Pretty tempting to cheese the logging using the manual loading tricks...
It's kinda amazing how poorly they have done the logging in SnowRunner, big downgrade from MudRunner/SpinTires in basically every way. You no longer have as much freedom to choose how you deliver the loads, and the loads are super uninteresting sizes. Delivering long logs in MudRunner was interesting because they were actually really long and required planning your route carefully, and delivering 2x short logs meant you needed a trailer that was a pain to back up and higher rolling resistance in the mud compared to the large/medium log dollies. Now you just drive back and forth with 1 bundle at a time, and the long logs are the size of the old medium logs. It's really slowed my progress in my game down as I can only stomach like 2 trips a night... But that's all I've got left to do in Michigan.
Yeah I'd second International for a one-make playthrough if anyone else is considering it, would be a better option than GM for sure but I just like the GM trucks. More options and variety, and some will be better suited to the Russian areas if you are planning to do those too.