For buses the national travel planner is traveline- https://www.traveline.info/
However, and it's a big however, that has become unreliable. It seems to be missing a fair amount of recent service registration data, so is missing services, or has out of date times.
Even at County level in the Lake District, the professionals are struggling to resolve that with Traveline.
The issues are not confined to the Lake District, I've had problems throughout the South and West of England- one issue was reported yesterday on a frequent service in Kent where data is incomplete. I've missed connections due to traveline and the associated bustimes.org website.
Southern Vectis (on the Isle of Wight) used to do a national book- long since ceased, but still a valuable broad reference tool.
Best to come up with a general plan- using Traveline as a broad planner- then it can be sense checked/refined here.
Likewise on bus tickets- there is no national list, but there are some superb value examples- like the Stagecoach daily and weekly tickets in the northwest of England (covers Chester/Manchester to Newcastle and Dumfries in one ticket) or the Blazefield group of companies in Yorkshire- one system wide ticket covers Whitby/Scarborough to Manchester and Preston. At some places it meets the Stagecoach ticket.
In the South of England there is a ticket which covers all buses and operators from Portsmouth and Salisbury to Canterbury (and the whole of Kent) or Heathrow and Gatwick airports, as another example.
The Lake District, as the average tourist sees it, is pretty compact unless you are getting off the beaten track. But yes there are many routes, and more coming on stream. The summer Lake District timetable book is now issued- but will become dated quite fast as the new routes are added, and other routes enhanced during the year. Moreover it has never included all services, with some glaring omissions like the 525 cross lakes shuttle and the Kendal Town services- such as the Oxenholme Station shuttle bus.
In fact it is probably dated before it's period of validity starts.
The value of a book is you see routes you wouldn't have even thought of- like a new Grasmere to Ullswater direct bus avoiding Keswick- once a day but still useful in the right circumstances.
On the trains there are some wonderful value regional rail rover and ranger tickets- see https://www.railrover.org
In the Lake District we have a brilliant local day ticket called the Lakes Day Ranger- which is a multi modal ticket (train, bus and Windermere steamers). Stagecoach have a variety of multi modal day tickets for the buses, and the boats on the various lakes (Windermere, Ullswater and Coniston).