Advice on a campervan suitable for 2 adults and 2 children (twins approx1 year through to as old as poss!)

Hi there. I was wondering whether anyone had any suggestions regarding a campervan that might be suitable for me and my family. We have twin boys who are 9 months now and we were hoping to find a small van that would sleep us all and have decent secure seating for the boys travel seats. We were thinking of spending about 5 grand, any advice on models or features to look out for would be appreciated