OK - I just did something similar taking with an allergic 2.5 year old (eggs, dairy, nuts etc) to a wedding in the US. Take as much as you feasibly can with you - even prepped cooked food stowed in a big cool box.
The other thing is to see whether the hotel can be some help even if you can't get a kitchenette. The hotel we stayed in was able to let us have a mini-fridge and a microwave, even though we didn't have a proper kitchenette. That meant we could at least store some food in the room and we could do some basic cooking in the microwave (she likes pasta and we managed to figure out how to do it). If you do that you could even take a big stash of homemade frozen food with you. (We didn't do this partly because I didn't think of it and partly because we had a long flying, so what we could take was more of an issue, but I do have a very organised friend who took 2 weeks worth of home cooked frozen meals on holiday for her DCs).
Otherwise, quick trip to the supermarket when you arrive to buy things she can eat.
Failing that, not the end of the world if she lives on bread and spreads, fruit, snacks etc for the couple of days you are there. I'd also be prepared to feed DD quite junky things out if it is something I know is very likely to be safe - for DD that would be chips, as its something easily available that is highly unlikely to have egg/dairy any other significant allergen in. But always have something (even if its only snacks and fruit) that you know she can have in reserve.
I'm afraid roomservice etc is not very reliable - our one attempt to order plain pasta for DD meant we got a plate covered in cheese. We sent it back and got a dish of "buttered noodles". Then lots of apologies and the offer of a glass of milk. It was so ridiculous, it was actually funny, even at the time.
Don't worry too much - I have to say, DD didn't eat a lot in the time we were away, but I think a part of that is picky toddler away from home rather than the allergy problem. Its not the end of the world, especially as you will not be away for too long.
I know this all sounds a bit terrifying, but for us it was all somehow OK - good luck!