I have two sets of cot sheet sets for each of the kids cots so when I take one set off to wash I can put the clean set on straight away. Also is handy for younger babies to have two sets in case they have a spew or something in the bed.

As far as blankets go, if you are going to put some on the bed I would suggest cotton rather than something like polyester. I guess it depends on how cool bubs room is and how thick the sleeping bag is to decide how many blankets you need. Right now in summer my twins are in air con so we have them in cotton PJ's (shirt and shorts), 2.5 tog sleeping bag and a couple of blankets, but their room is fairly cool, for us we have found this works best.