Bicycle routing app

I need expert with maps to help me create one feature for my Web. Feature is drawing long bicycle routes, save them as .gpx and load .gpx to map again. Also, I need elevation chart to be created for the route. Important: Routes can be longer than 1000 km and you should be aware of API limits. Google Mpas API is not very good for this, I recommend leafletJS and maybe MapQuest, you should advise me what is the best option for this since I can't find the solution and good developer for some time now.