Hi Mike, When I orginally read your post I waited to answer because I know of several with more first hand knowledge than myself. For example Rif Adams, and Terry McAllister have both made long trips using the Whizzer motor. I must say I think the Whizzer motor is much easier to work on than the average lawn mower because it doesn't require any special tools to service [flywheel puller, ring compressor, etc]. I can totally rebuild a Whizzer motor in less than one hour, and usually takes more time to remove and install the motor than rebuild it. Because of the massive needle bearing crankshaft, the "flat head" design [less moving parts], and the fact that it is a 4 stroke motor would make it one of the best choices for a long trip. But a word of caution, the majority of expected problems would center on the initial prep of the bicycle, and tires. The current Whizzer NE motor is by far more durable than the earlier WC-1 offering, and should be the only motor considered. I have several special modifications that can also be effected to make the NE motor litterly "bullet proof". I would also consider using the manual clutch version because of the simplicity [less moving parts], and installing the belt tension kit #3010 to allow using the same front belt for a long time. The kit will allow the adjustment needed when the front belt starts to stretch or wear.
Hope this information is helpful, and as always I will be happy to share any information or test results that may help.
Whizzer OuterBanks,
Quenton