the moleworth is just a slightly under maintained gravel road.So many choices for bikes now.Being a reasonabytalll fella an adventure type bike will suit you.
an r65 would proably be slower than one of the 250s you are talking about;Even my r100 gs only had about 60 hp.If you happy with a single a bmw 650, klr 650 or a suzuki dr 650 ..THe bmw 650 actually a rotax engine.I prefer twins myself.