Four files here to download. First two are the standard route, then there are alternatives depending on how we feel:
Aberystwyth- Newton
This includes some off road sections where walking may be needed (using NCN route 818) 47 miles, 4400ft climbing
https://ridewithgps.com/routes/43545225
Newton-Shrewsbury
Follows the NCN route along canal towpath initially, 41 miles, 200ft, just one climb
https://ridewithgps.com/routes/43545309
Aberystwyth-Newtiwn via Elan Valley
Avoids the tricky off road section, adds miles but does take you to Elan Valley which is stunning. 61 miles, 5100ft (!!)
https://ridewithgps.com/routes/43545871
And finally a hill-free route back to Shrewsbury 32 miles, 900ft