In the end we did not Tow
Although it was not all smooth sailing and one that brought memories why I do not like follow the leader over long trips with my wife driving another car
When I went to get the trailer my mate turned around to me and said dont tow it with that, pointing at the BX. He reminded me of two really nasty hills on the route one I had forgotten and then told me how many trucks and Caravans he had rescued from that hill/mountain.
Ok cool I can now go the shorter route which for some reason the locals hate simply because its twist and turns and past reputation of being most metal (Kiwi for Gravel

)
Set off at 9 am from home descended to he nearby town the start of the route which is in a valley where two rives meet. On goes the headlights and consideration to flip a foglight on
2 hours 30 minutes later and a 153 kilometres of interesting road with a classic 15 yes 15 kph marked bend and what is now only 12 kms of remaining unsealed road. We were in Citreon Country, or so we thought? Saw 4 modern Citreons of models not familier

but no BXs.
Another 20km later we found our goal, the Red BX16RS we were going to use for parts. The owner gaves us $20 discount because it was low on oil so we paid $180 for the car. The owner was of a mind that the car might not make the trip back. Well to be honest I was not sure but of a positive mind hand my fingers crossed it could tackle the rather step hills on the way back.
Basically thye Car did not have the Legal Paperwork to be driven on the road. But it started and ran and once we got back to the Forgotten Highway to odds of seeing a Police Car was as remote as seeing more than the 20 cars we had passed on it heading the opposite direction.
60km from Stratford I was as predicted a few kms up the road from the wife who was following in the 19TZS sitting on a saddle looking for her to come up the hill to get a motion photo
5 minutes passed and I was worried evntually after backtracking 5km the sight of a car with bonnet up sent shivers down my spine.
The dreaded water light had come on, she topped it up but further on the same thing happened that point I gave her Red (the 16RS) to drive and nursed the 19TZS on. We stopped at the only cafe halfway to cool the car down to check the water again, bit no it happened again.
I figured that it was because I was following my wife at a slower speed than I would like and the same was true with her driving. The car was be put under load to much. With Daylight fading at 4pm I told her to go on gave her a 10 minute head start that 40 minutes later once we hit the more open road again I was breathing down her tailpipe
Took 5 hours to get home

Could have been worse if I had the trailer I guess?