Hi Cris
while your idea is a very good one, I'm just going to hurl in a note of caution here, and it is all to do with the stage your wife is at. I don't know the stage, of course, but you can judge that. Early stages - fine, mid and later stages, just be careful!
My wife Jan grew increasingly ill at ease in the car as her condition progressed.
The last long trip we made was to Cornwall. We had to return early because she was very agitated. Halfway home she grew very restive in the car, so I pulled into a lay-by for a short break.
At that point Jan grew even more agitated and wanted to get out. I knew that, in her condition, in the middle of the countryside by a busy road, this would not be a good idea, so I told her that 'home' was just a short distance further.
For the remainder of the journey, some 2 hours, I had to constantly reassure her, with the doors all locked, as we drove along - not the best way to be in full control of a fast moving vehicle. We made it, thankfully.
I just pale at the thought of being somewhere on a road - country or otherwise - with a partner on the back of a tandem, and with their suddenly throwing a mental wobbly. Safety, stress, etc all come to mind.
So, by all means have a go, but always be prepared for the unexpected.
