I stayed at Catherine's house for almost a month while working in the centre of London. I can only recommend for both short and longer stays. Firstly, it's really conveniently located: you can reach the house from the centre of London either by tube & bus (W7) that stops at the doorstep or by a bus 91 whose stop is at 3-minute walk (I'd usually choose the latter option as I wasn't in a hurry). The Crouch End itself is a lively neighbourhood and has everything you might need: you'll find here a lot of cafes, pubs, cinemas, shops etc.
Catherine's house is marvellous: the space is airy and tastefully decorated. Before I'd come to London I was afraid the room might be small but it turned out to be a perfect place for both late evening work and relax. For me the major pro is that there are 3 (yes!) windows (each on different side of the room) which makes that it's surprisingly bright regardless of the weather. Secondly, the bed is supercomfy. The whole room is practically furnished and cosy without being cluttered. It was really a pleasure to get back in the evening. The en-suite bathroom is great and so is the kitchen. As others have already said Catherine would provide you with yogurts, juices, a vast selection of teas and coffee, not to mention the delicious self-baked bread... You can then prepare yourself a solid breakfast. Whenever you like you're also free to reheat or cook your meals. I don't need to add that the house and the room were spotless clean.
All in all Catherine is a perfect host. She's friendly and welcoming, but at the same time discrete. She may be sometimes very busy but is always reachable should you need any help or suggestion. Highly recommended!