shorten the dynamo

["Slack Alice" Simon]

Or, to keep things simple and to get it out and about quickly:   with a conventional radiator you will get away without a fan unless stationary on hot days or trundling up steep hills.

Charging the battery will keep you running all day, unless you are using headlights and the starter.

Starter is the problem, unless you carry two batteries - but if you are not doing lots of stop - start, I wouldn't worry too much.