The FFCT (French equivalent of the CTC) had their Semaine Fédérale there the year before last. You should still be able to get details on that. St Omer is itself flat, and it is fairly flat to the north and east but nevertheless with some fairly vicious hills, to the west it is quite hilly. There are quite a lot of sites connected with the two world wars. It is an interesting area, not very touristy, if you like Belgian beer there is a lot of choice from the local brews, and it is not that far from Belgium.