Three of the four around the old ground are still open - The Princess Royal on the south east corner closed down, which was the most miserable of the four anyway. It’s about a 20 min walk from Griffin park to the new ground. There is a really decent large pub right next door to the new ground - The Express Tavern, which I assume must be rammed on match-days. Or if you walk a few minutes towards the river there is a newish Fullers pub called One Over the Ait which is pretty large and nice. The other option is to walk down to the river and head west. Within ten minutes you’ll see about four pubs on the north bank - The Steam Packet, The Bell and Crown, the City Barge and the Bulls Head. If it were me I’d go for one of those four - especially if it’s a nice day and you can drink outside, personally I prefer the Bulls Head but it’s the furthest away.