apushatayid – my personal feeling is that it might not be assur to read a magazine while using the facilities (although it is probably better to try to avoid it) – since you can’t do anything else anyhow (kind of like the idea that it’s not a problem of Bittul Torah, although it’s not exactly the same), but to stay longer to read would definitely be assur.
In terms of sitting on one’s bed: I don’t think there is any heter to sit on a bed. Lying in a bed in order to sleep is obviously mutter, but I think that one should try to get up as soon as he wakes up, and not remain lying in bed awake for too long.