Getting to the ground
Of all the new grounds built in this country in the last 20 years, Brighton's is possibly the worst in terms of access and amenities. The American Express Community Stadium (or Amex Stadium for short) is around 4 miles from the town centre in Falmer, next door to the University of Sussex campus. There was obviously nowhere else that the club could possibly have obtained permission to build, because if there was the ground surely wouldn't be here.
There is limited parking at "car park B", which is a 10 minute walk from the ground. It must be booked in advance though (phone 0844 3271901), and it'll cost you either 13 or 15 quid depending on when you book. Other than that there is nowhere to park within around two miles of the ground as all the streets are residents' permits only. Most people understandably therefore use the train (to Falmer, next to the ground) or Park & Ride to get there. In either case it can take up to 50 minutes to get away from the ground. The good news is that use of buses and trains to and from the ground (from 14.00 to 22.30) is included in the cost of your match ticket. There are two Park & Ride schemes, although only the one based at Mill Road ("Park & Ride 1") is much use for away fans. As for the trains, you only have to buy a ticket to Haywards Heath as your match ticket covers you beyond there.
If you're travelling by rail then you have the option of heading for either Brighton or Lewes, and then catching the local service to Falmer. There are four trains an hour from either, with a journey time of less than 10 minutes, and additional trains immediately before and after the game. There's a more frequent and slightly quicker service from Victoria to Brighton than to Lewes. However, it's much quieter (and therefore quicker) travelling from/to Lewes than Brighton.

The only pub anywhere near the ground, the Swan Inn in Falmer, is strictly home fans only, as is the Ruby in Coldean. If you've driven down you'll therefore have little option other than to eat and drink in the ground. The good news is that the quality and service are supposed to be good, and they serve real ale.

If you travel down by train then there's a good selection of pubs just outside of Brighton station. Best of the bunch is possibly the Evening Star, only 2-3 minutes walk down Surrey Street. But the Lord Nelson, Prince Albert and Battle of Trafalgar are all decent enough. If you decide to travel via Lewes then there's also a good choice. Nearest to the station is the the Lansdown Arms which is a great little pub. However, it'll be heaving, so you'll probably want to walk straight past it and up the hill. Worth a look here are the Lewes Arms and the Rights of Man, or turn left out of the station for the Kings Head. Possibly the best pub in Lewes though is the Brewers Arms.

Pub map
Football Ground Guide
Away fans guide (from official club site)
Matchday travel YouTube video