While I've never been to this particular show, the programme for last year would suggest that in addition to the Sheep Dog Trials/Competition, there are a host of other events taking place involving other breeds of dog. It's hard to tell from the Rick Steves video (low cloud apparently!) if that is in Patterdale, but it will be a very similar show. And if you feel up to it and are that unique combination of superhuman and mildly unhinged you can even enter the Fell race, which is for humans! (I've done several fell races and am not remotely superhuman or unhinged enough, which is why I don't do them any more. Well, not often!). Better yet, last year's website advises that yes, there is a beer tent!
Patterdale is a great part of the Lakes and if the dog show doesn't keep you occupied there are other things to do - plenty of walking or if not up for that, then a trip on the lake on the Ullswater steamers. There's Aira force a waterfall nearby where it is believed Wordsworth (or dependent on who you believe, his sister Dorothea) first saw the 'host of golden daffodils'. A drive south will take you to the Wordsworth's home at Dove Cottage, Grasmere.
Only word of warning is that it is likely to be very busy at that time of year, as I believe, it's a Bank Holiday, but don't let that put you off! Have a great trip!
Ian