A few people on this page have mentioned the program tyre for pre planning a route for your garmin or tom tom .
the tyre program if you dont know has gone tits up , due to the free program not having the google maps licence anymore, but this is no problem just switch to
https://www.myrouteapp.com/routelab this is the other side of the program that is part of the tyre company you can use it on a free option , but i can promise you it is well worth paying for the year licence as it gives you better map options and opens up different route planning options, it takes a little while to get used to but on the main page just click the new routes tab and give it a go, then all your routes will be in your routes tab to get again.
you can get the full program for a short period to try it out but it then defaults to basic again, you can continue using it in basic mode but the paid mode is better, i suppose it depends how much you like it if you think its worth paying for
I have the ten legs of our poland trip all logged and saved using this program all ready to stick into the tom tom rider 400
i have found the tom tom rider to be a perfect scooter option coupled with the program listed above, i am using the varitronic kit to power it via the trickle feed going to a small battery located behind the leg shield wheel carrier and it has worked well this way for years