That's a pretty tall order. I'm not sure you can fulfill all your wants. I do not have a Goldwing trike, but I have ridden them. Seating is pretty neutral, not as obviously cruiser-style as the Harley Tri-Glide, for instance. For a true cruiser-style stance, you would probably have to go aftermarket with either of your selections. In the Spyders, you would have the most mods to make to the sportier RS model. There are both highway pegs and footboards available, but the standard seating puts your feet well behind your knees, even with short legs. The RT has a more neutral seating position, but definitely not feet-forward. The Spyder spreads your legs quite a ways in that stance, making for a longer reach, so adjustable highway pegs might be best for a shorter person.
The Goldwing has the most back support in that seating position, followed by the RT. The RS has almost none, just a small bumstop. You may want an aftermarket seat and backrest for any of them, if you lean back at all. Lots of people swap seats for the comfort alone...with any bike. A seat is a very personal thing. My wife is 5'2", and she leans forward no matter what she rides, so a backrest may not be an issue for you.
Handlebars on the RS are forward, so risers or replacement bars would be a must. My wife found them essential when she went to the BRP comfort seat. Bars are pulled back on the RT and the Wing, so I expect you would be fine there.
Either Spyder has sufficient power for you to keep up with (or ahead) of a group of Goldwings, although 3-wheelers are usually kept to the rear of a group ride, for safety reasons. (Except DocDoru, who is so far ahead they can't see him sometimes.

) The Spyder power is higher in the rpm band, so you will have to use the gears. A Goldwing is a low rpm, torque monster. Very few machines can compare. You will absolutely have to stop for gas more often. Spyder mileage won't challenge a 2-wheeler, and the gas tank size limits the range. You may rival a Goldwing trike in mileage...or at least come close, but I believe their range is also farther.
Go sit on a couple of Spyder models. See if they "fit", or what changes you would need. Take a demo ride or two. You probably won't be able to sit on a Goldwing trike, unless you happen to be near a conversion dealer, or know an owner, but you could sit on a plain Goldwing to compare. I might suggest you also try out a Tri-Glide. I don't like forward controls, but it was a comfy ride, and ther may be some deals to be had this winter.