We did a bike packing trip there last year. Flew into Dubrovnik and cycled the ciro trail to mostar. It’s an old railway line so not technical but passes through some amazing countryside.
After Mostar, we made out way back to Drvenik on the Croatian coast. Then got the ferry over to Hvar and cycled the island south to north.
We then island hopped on the ferries back to dubrovnik via Korcula.
This was over 7 days.
Best tips:
We used a hostel for the first and last nights in Dubrovnik so that we could leave our bike bags.
We did take a tent but as the season had drawn to a close, we found a place on booking.com each night. Dont think we paid more than €30 a night!
The ferries are good but you have to book with the individual ferry operator, there is no central website for them all.
Although I hate komoot in the UK, it worked amazingly there. HOWEVER, when planning a route DO NOT use the mtb option, use the gravel. The mtb one tried to take us on some hard-core hike a bike but the gravel option was brilliant.