I try and avoid Antwerp if I can in favour of Ostend. Always seems to take an age to get fuel and out/in security, but then I'm just picky.
Flying Belgium is a piece of cake. No problem at all flying in the Brussells TMA at FL50.
If you're in a single and coming from the south east, I'd go Manston - KOK - Antwerp. Easy peasy.
Have fun.