Installing an auxiliary transmission cooler would be good insurance if yours in an automatic. I put one on my 84 245. Probably cost you about $60. It mounts in front of the radiator. If I recall correctly, Volvo recommends the automatic for towing. Seems strange, because every tow truck I've driven has been a stick, though they don't have to be. Maybe it is because an automatic is pumping oil into the radiator and is more coolable than a manual. My sense is that a stick would be fine, or even superior. The rear end doesn't have active cooling, and it's also under more stress with towing.

Good synthetic ATF installed in mine, too. More reassurance. Fresh clean engine oil is good. I have some IPD overload springs, because I haul a box trailer a lot, and it allows more weight on the tongue without sagging. Shouldn't matter with a tow bar. And thicker 'turbo' anti-sway bars front and back ad more security stability-wise.

Towing is an adventure- an 'event', and going slow will still get you there. You have four wheel disc brakes, which is great. If yours is sound and maintained all around you can just go for it and will likely be fine, IMO. Keep it out of overdrive, even on the flat. Presuming an automatic, it keeps cool before the hill and helps cool after the hill. It's worth some extra gas. That's Volvo's recommendation, regarding towing.

Steve