http://www.felinecrf.com/

This is the best website for cats with chronical renal failure.
Of course no story is like the others.
Vomiting is a bad sign and does not occur in the earlier stages. But subcutaneous fluids can change a lot.
Filou goes to see the vet for his sub-qs as he is by far too wiggly a little worm to get them from me. But I know that many Pettalkers administer them themselves.
Another important thing: they shouldn't lose weight. They rather can have the most yummy food even if it contains too much protein- but if they lose weight they are using their own protein
So all nice things like cream, egg yolk etc. are good to help them keep their weight (just opposite to us ).
All the best for Braveheart.