Bikepacking - a viable alternative to racks & panniers

Okay, I've got 10 days off work at the end of April. I'm Bristol based and keen to stick to public transport for getting to/from wherever I'm going. What bikepacking trip would you do with this time? Current candidates:

1. Sailrail to Dublin and then down into Wicklow
   
2. Train up to the Lakes, some sort of loop up from there towards the border.
   
3. Train up to Scotland and then ?? (weather may not be great)
   
4. Some sort of route from Cardiff up to Holyhead (ditto on the weather)
   
   

I'll be taking my Surly Troll, so light MTB and wild camping are the order of the day.