Depends how much you are taking. I have 3 different wheeled vehicles. One is a match trolley to take a seatbox and carryall, one is a carporter barrow with rear wheels and one is an ordinary folding fishing trolley which has proved fairly robust and takes chair, rucksack and big bait bag . Its light, small, easily manouverable and is my preferred option for day trips. One thing however is that they tend to have a short axle and can turn over on bumpy ground so a I bought a longer round steel bar to make a longer axle. Also you have to be careful that your rucksack does not droop at the ends and act as a brake on the wheels (just noting pros and cons). In your situation I might buy for £40 eBay item number:
332491499114
FOLDING FISHING SEATBOX TROLLEY COMPLETE WITH TROLLEY BAG which has wide wheels and bagging it avoids mud in the car. As I get older I would like a sit on - on one Wye trip at a golf course they gave us a sit on golf cart to use!