Seth - the short answer to the “rule of thumb” question is get a torque wrench with a (for example) 0 to 150 ft-lb range. They’re not that expensive and – as concerns axle nuts and such – probably worth the cost.
[There will no doubt be posts to this thread in the (apologies to Alfonso Bedoya, “Gold Hat” in “The Treasure of The Sierra Madre” staring Humphrey Bogart, Walter Huston and Tim Holt) “Torque wrenches? We don’t got no torque wrenches; we don’t need no stinkin’ torque wrenches!” vein, but I would ignore them.]
The longer answer is that there is a way to extend the range of torque wrenches as illustrated in the “Snap-on Torque Computer” (Snap-on Form No. SS-306A. copyright 1965 by the Perrygraf Corp. of Maywood IL) that I obtained who-knows-where when I was a practicing engineer. This is principally for use of extensions, off-sets and crows feet with a torque wrench, and involves figuring the effective length between the item being torqued and the torque wrench handle pivot point, essentially based on the "100 lbs exerted 1 foot from the nut/bolt receives the same torque as 50 lbs exerted 2 feet from the nut/bolt" concept.
But I think the short answer approach is better.
Whatever you do, don’t fall for the “spot torque” response I got from one of the individuals I worked with years ago when I was chief engineer of a nuclear power plant. I was walking through the shielded tunnel one morning during a valve operation and inquired if the operator had the correct torque information for the primary reactor system valve he was operating (always a sensitive subject on reactor plants). His response was “No problem, Eng - we’re spot torquing this valve.” When I “bit” and asked what spot torquing involved, he responded – with a straight face – “Just pull on the torque wrench with both hands until you see spots before your eyes.”
Don’t spot torque Model A axle nuts…
