First I'd raid the nearest book store for "how to survive off the land, farming, survivalist" type books as, once the internet/power etc goes (say within a few days), 99.9% of the people left won't have a clue how to live sustainably. Then I'd hit a chemist for some antibiotics then a Go-Outdoors/Blacks type place for some more camping type gear. Probably make a few caches around the local area of heavier bits and pieces too.
The roads would be carnage with all the dead filled crashed and burning cars, lorries, buses etc so you're not getting out "on road" for a while so, unless you have a proper 4x4 which can actually go off-road (not just a Katie Price Rangey with a set of road tyres), you'll probably be walking a lot so bear that in mind too. Military bases will still have some folks around, you "might" be able to pick-up a rifle or two and a small amount of ammo from whoever died when guarding the place but, unless you were there when it happened, you'll probably be too late to get anything other than a welcoming shower of 5.56mm goodness coming your way
The big choice would be "stay or go?" - Somewhere like Stoke would drop to 2500 people, thats still enough to see people about and have enough food/water in the hundreds of thousands of supermarkets, shops and homes etc without ever fully emptying the place so you could Stay, but then the dead would rapidly become a health hazard alongside some of the locals, so would you Go?