Grampa-
Gongrats on the retirement! While my wife and I are at the far end of the scale from your retirement, we tow with a Ford Ranger. The truck is a 1999 4x4, 5 speed automatic, 4.0L V-6. Rated to tow 5600 lbs. and the GCVW is 9500. Our TM is a 1990 M-26, or in today's models a 3023. Labeled dry weight on the TM is just under 3000# and GVWR on the TM is 3990#. I have been pleased with the combo, towing from New Jersey to Maine, Yellowstone; Durango, Colorado; Grand Canyon; over Wolf Creek Pass, etc. Guess we've logged between 7000-8000 miles with it in the two years we've had the TM. I use a Equalizer brand hitch and am pleased with it.
Now, the Tacoma. I would suggest that you stay with the 2619 or 2720 series. That said, I feel the Tacoma would be working hard. Don't forget about frontal area when you are calculating towing ability. Remember that most TMs with popular options are 300-400# heavier than dry weight stated on their website. To that add your cargo, propane, water, battery.
I get about 12-14 on the highway with the TM, 16-18 without. I don't tow in OD (5th) at all.
Please don't forget the WD hitch. Keeps the front end of the TV down for good steering and breaking. Without it (or if it's improperly adjusted) my rig feels light, tends to plow in turns and front brakes tend to lock-up. If you have ??s about all this, please ask here. Also, a good brake controller like the Prodigy.
If you are going to travel extensively I suggest getting the books Mountain Directory East and West. Very, very useful. See them at
http://www.mountaindirectory.com/. Descriptions of most heavily traveled major grades in the US. They tell you what to expect both going up (easy) and down (go slow!).
Your gonna love the TMs!
Anyone else got some thoughts here for Grampa?
Camperboy