We planned our trip for last Sept with the plan to only use Trains and Buses. Here are a few tips of what we learned:
1 Key advice is to ask on here. there are some very helpful people that know their stuff and can give you great advice.
Buses are local. Coaches are the Bigger buses between routes. This we found out when a friend thought one thing and we thought another.
Know the final destination of the Train you are going on. They often announce and post this on the Announcement boards.
If you buy advance tickets you get a deal and the train will not necessarily let you on an earlier train.
When planning your itinerary and using Buses check to see when the buses will run. In Yorkshire Dales there were more buses on the weekend out to Bolton Abbey. We were there mid week and had 1 day to choose from Wednesday. You needed to go to Grassington and then to Bolton Abbey. and we did this return because we didn't plan to go into Ilkley. In the Cotswolds there are NO buses on Sunday's but more during the week. So, just look at this when planning your itinerary.
Hadrian's Wall area Buses- AD122 are only every 2 hours. We found that 2 hours was a challenge . In some areas not long enough but 4 hours too long. It's okay if you have lots of days. We only had 2 and 1/2 days. They are having trouble with attracting bus drivers so they just don't have the extra spots.
That's my main thoughts.
Hope this is helpful to you.