Hi Ian,

First up, I think you'd find a pickup such as the Ranger much less comfortable and much noisier than a road car such as the Tucson, so I suggest you don't go down that route - assuming that high mileage is racked up on the main road in any case.

The issue with changing every year is that you're taking a massive hit in depreciation every year, increasing your overall costs significantly. From the information you've given us, I'd suggest that changing every two years would be a more cost-effective strategy, especially once the price of used cars readjusts from the high level we are still at today. 

No harm in talking to a few different dealers to get their take on it, as well.