A/R is typically done on defined A/R tracks at FL200-260 and 230-280 kts, depending on the receiver.
Yeah, that's about the ball park. Refuelling speeds for fixed wing types tend to range from just over 200Kts IAS for an old Herc (the C-130J is capable of refuelling at far higher speeds), around 250kt IAS for some light attack aircraft, and then the fast jets tend to go in the 270-300kt bracket - 280kt is the generally the norm though, but on request some types will ask for different speeds.
Height wise, historically the mid 20s (1000s of ft) have been the upper limit due the engine performance of the receivers (there's no lower limit as such, other than that dictated by any enemy threat!), but certainly newer aircraft are far more capable, and refuelling at 30,000ft and above isn't unheard of.
