I was amàzed to get useful info so soon in reply..

Many thanks to those of you who thought about my posts..
Very kind indeed!!...
Must consider each one carefully as right now...Ive got quite a useful newish trailer...but an 25 year old Peugot heavy duty road bike to slog up the hill...
The info about hills...is grim
I can see that it will take more than a few nuts and bolts and the cheapest kit available to get me and the dawg to the top of the hill...
I dont care at all about style...
But yes...guess there may be probs with road laws here...if I get too creative with big lawn mower motors or scrap motor bikes...
There must be a cheap way to do this...
A three wheeler would be best I think...
Praps pillage parts of two other bikes and build an own design..
I have almost zero money...but that doesnt usually stop me trying to make things..
Yes...the laws....tho...could be a stumbling block....
There's a magnificent scrap yard not far away...with every kind of discarded metal thing ever invented...in mountains. Would it be possible to adapt an old motorbike motor? I imagine that has more power... Than most cheap bike kits.