I'm kinda looking at a 2003 Road King with low mileage. I'm a short guy 5'5". What's the lowest seat Height I can get out of this bike?

 

Seat height numbers don't mean a lot, especially on Touring bikes. It's the width that will keep you from getting a foot down flat.

 

Go and try it for size! There are various ways of making up for short legs, such as thick-soled boots, trimming the seat around where your thighs reach down, reducing padding thickness (I use a Corbin). Lowering the suspension will reduce ground and cornering clearance and may reduce ride quality.

 

Im 2" taller on a 04 RKC with an "Ultimate" seat and bike was way too tall. ***** of feet only.
Thats a lot of weight to support on mostly toes.

Shaved seat (myself)
1" shorter shocks
Thick workboots.

Now Im good.

ymmv