I forgot one inexpensive fuel economy 'trick' ... change your engine oil and oil filter. For longest engine life, every 3 months or 3,000 miles.
Whichever comes first. If you reach 3 months without 3,000 miles on the odometer, it usually means lots of short, stop-and-go trips. These result in a buildup of hydrocarbons in the engine oil. Atmospheric humidity combines with the hydrocarbons to form acids, which eat away at engine components. (Especially crankshaft and rod bearings.)
If you pass 3,000 miles in less than 3 months, if usually means longer trips. Longer trips gives the engine time to warm up completely, causing the hydrocarbons to be evaporated and expelled through the PCV system.
Change the oil and filter before putting your motorhome into storage. Run the engine just long enough to build up oil pressure and circulate the new oil completely. It's not necessary for the engine to get up to full temperature. A few minutes run time (not more than 5 minutes) is sufficient. (This flushes the acids out of the engine's oil passages and dumps them in the pan, where they won't do any harm.)
Fresh oil means better lubrication ... and more power going to the rear wheels.
10W40 oil leads to longer engine life than lighter 5W30. However, this comes a slight expense in terms of fuel economy. Automobile manufacturers now recommend 5W30 to meet EPA standards. (This may be a case of government regulations being "penny wise and pound foolish." It may take more energy to manufacture and ship replacement automobiles -- and engines -- than is saved by the EPA standards.)
The engine life/fuel economy trade-off is up to you. It takes a slightly larger portion of the engine's power to pump the heavier 10W40 oil through the engine. Because motorhome engines often last decades before needing rebuilding or replacement, the slightly better fuel economy offered by 5W30 may be preferable.
Note: 10W40 is advisable if you plan to spend a lot of time driving in higher ambient temperatures. (90 degrees F or higher, such as in southwestern U.S. deserts.) I've always used 10W40 and the rest of the vehicle usually wears out before the engine. However, we now run 5W30 during the three winter months. 10W40 gets too thick to start the engine at the seriously subzero temperatures typical during interior Alaska winters.
