I live in Nuneaton and work in Coventry so here is my input.
Parking - street parking is difficult as it’s all permit holders only. There is a couple of match day car parks on winding house lane, I think it’s £10 and a 10 minute walk to the stadium.
Pubs - it will be difficult to find anywhere to get a drink before the game. There are a few pubs in Longford but these are home fans only and given our past history I’m sure there will be a large police presence.
There is a green king pub called the bull and anchor in Ash Green (15 to 20 minutes walk) that does normally allow away fans that maybe an option.
My advice would be to get the train to Nuneaton and have a few beers there. There are a few pubs within 5 minutes of the station, The Weatherspoons opens nice and early. Then even jump on the 48 bus (£2) which takes around 35 minutes and drops off close to the stadium or if there’s a few of you get an Uber, only 15 minutes away and looking around £15.