If you like Pulsars, then you should try out one of the newer examples on the 24, sometime. It's not an unchallenging route, either, as it leaves Durham - they're really good on steep banks and sound great, too.

It's also possible to do all the places you mention on an arriva day ticket instead of an explorer, saving you a couple of quid. If you travel to Peterlee, then you can change onto the 21 for Darlington or the 21A for Stockton & Boro - that's often an OmniDekka of the unrestrained variety. A bit tired inside, but a bit of a rollercoaster ride on some of the windy country roads and put the Pulsars to shame going uphill - they're not limited to 50mph like the GNE ones and really have a lot of oomph.