Route Planning to Mandello

Hi
Planning on doing a European tour this year and wondered if anyone has any suggestions of decent route planning apps or websites? Alternatively does anyone have any good route suggestions that they have used previously.
The plan is to take Hooch back to Mandello del Lario sometime in the summer months (probably July due to the museum’s longer opening hours). I can read a map and will quite likely end up planning my own route there and back,but would welcome some ideas from people that have done it before.
Not aiming on a quick blast there and back, this will be for a couple of weeks at a fairly leisurely pace.
Haven’t toured on a bike for a good few years although I used to go to Germany on a regular basis in my youth, though in those days it was on a variety of Japanese machines (well one year was on a CZ) as couldn’t afford to get my Guzzi till 5 or 6 years ago.

Are you camping en-route, or hotels?
When I went to Mandello in 2015, I went via some relatives in Austria so crossed over by tunnel, then followed pretty much along the Belgian border for first day. Stayed in cheap B&B’s on the basis that anything with a bed and a roof is better than a tent. Second day was quite long (450 miles) so jumped on the motorway near Colmar and went via Switzerland to get to relatives’ place near Lake Constance. Third day was then quite short, only about 150 miles. Through Liechtenstein, back into Switzerland and then Spluegen Pass into Italy. Got to Mandello mid-afternoon.
Coming back, the weather was awful, so headed down to Como and then Swiss motorways again for convenience. I think it was snowing up on the high passes but only raining below. Sunnier in France so back roads to Vittel (where the water comes from). Then pretty much a straight line back up to Calais only using back roads.
I quite enjoyed the Vosges area, so might go there this year if I can string together enough days of holiday.

I have done it a few times
but i never bother with route planning apps or satnavs
I use large scale maps and plot my route on cards with prompts and directions
occasionally I will look on google earth to see if any interesting is near my route
but I like to keep it flexible

I have been a few times but time is of the essence usually. So I generally take the fast routes

Via Michelin is a good route planning site.

https://www.viamichelin.co.uk/

I hope you will enjoy exploring the area. It is wonderful

Have a great trip.