I’m only a couple of weeks into Zwifting and loving it so far. I would love to be able to select a series of routes to ride through in sequence. Before starting I could pick a flat route to warm up followed by some climbing routes and a flat route to cool down. It would be nice if we didn’t have to end our ride and start a new one each time. If there is already a way to do this that I don’t know about please share 
Hi @Michelle_Parry_Wild and welcome to Zwift!
There is no way to link up multiple routes, if you’re trying to get route badges then you need to start a new ride for each. Depending on what device you use for Zwift, its quite easy to start a new ride on PC for example.
Welcome Michelle! I’m new-ish to Zwift myself (just this winter) and upvoted your request because I think it’s a great idea.
Adding to that: a “route builder” so we could pre-plan a custom route turn-by-turn - or daisy-chain existing routes - would be awesome. Right now, you have to manually use the turn buttons.
Not exactly what you want but have you tried ZwiftMap.com, and ZwiftGPS.com? The former is great for visualizing routes, the latter will link with your Zwift account and display exactly where you are on a map. (of course you need another device to view these while you’re Zwifting)
ZwiftMap.com even has a “Custom Route” option so you can measure route distances and elevation gain.
Thank you! Imagine the discussions that would ensue about how best to link the different worlds’ routes together. Would someone come up with an epic EFI? Hopefully they can add this feature :). I’ll look into the other ideas as well!