In my opinion, the food wasn't actually that bad! Even when I moved out of halls I still went to eat at the dining hall from time to time; it's really cheap and the portions are huge. However there is also 'The Hub' which is the other dining hall near WTB, which sells even better food and is available to everyone at a discounted price.
In regards, to the mini oven/hob you could definitely get away with that! Everyone does it. I kept a kettle, toaster and mini fridge in my room and managed to get away with it for a year
. I got the fridge because of the food thief's in my corridor...honestly, some of those girls were something else. Beware of the shared bathrooms though, Founder's are the only halls in RH that do it and it can get a bit nasty sometimes. But you don't mind sharing a bathroom it's fine.
Also, the corridors are single sex. 2nd floor is boys and the 3rd and 4th floor are girls (5th floor is postgrad). All the other halls are mixed.
Socially, RH is wonderful! You'll make friends very easily with everyone in your halls if you put yourself out there. I've seen people say there's nothing to do but SU twice a week, every week (SU nights were just hilarious), Monkey's Monday at the Monkey's forehead (student pub), Medicine (bar) on Thursdays and Saturdays + Liquid club in Windsor will all keep you occupied socially!
If you want halls that are a bit more wild maybe pick WTB over Founder's only because Founder's have a 'no guests after 11pm policy', which was just completely lame and annoying (although if you're a sneaky rebel like me you can successfully sneak people in...flirt with security, it's fine). The flat parties at WTB were some of my favourite uni nights!
Tbh, wherever you stay you'll have a great time at RH. It's a big campus but really becomes a little community after a while. Hope this answered your question