How would I know which frame size I would need from brand to brand?
this is the quandry that we face, from brand to brand, on fit and frame size. Since some bikes are compact geometry (racing/road) and some are relaxed geometry (Road/touring), a 54CM bike might be the equivalent to a 58CM bike because the tubes are different length for each style (sighs)
A broad starting point is standover... only a starting point! If you can straddle the top-tube, flat-footed, and lift the bike, and the Top Tube travels a a couple CM before it hits the family jewels, then you are in the ballpark. If the tube is tight against yer crotch, or you can't hardly straddle, then it is too big... if you have to lift the bike quite a ways before it hits, it is generally too small. Of course, if the bike has a sloping TT, then this goes out the window... sort of. If it is too big or small, your seat placement, how long you reach, or pedal angel get exaggerated.
generally if you are that height with that inseam, a 55CM seems too big
The Jamis site says this about the Aurora:
The Aurora is one of the most versatile bikes on the planet, good for club rides, off-season cyclocross racing, light trail riding and, when kitted out with racks, commuting and touring.
The Satellite is basically the same with a slightly lower drivetrain, CF fork, and such... but same quality steel frame. The have eyelets for racks and water cages
I think any bike could be suited to touring. You can get hard core tour specific rides if you get real serious. These would work for modest level touring with some loads... they are good all-round rides
do some searches for Jamis and touring
here is a thread that includes Aurora
affordable touring bike?
Good, inexpensive bike suggestions?