I'm 5"6 on a good day and I would be considered youngish (35). I could understand stepping in and out would be an issue if there's a certain lack of agility. In that case, it would be wise to consider getting the step through instead.
As for stopping and staying on the bike, I do the same thing on all my bikes, I just move from my saddle and my inseam is just high enough for me to stay above the top tube and put my two feet on the ground. Again if there's an issue here, getting the step through would resolve this.
I never felt the bike to be too high, on the contrary since the handlebar is quite close to the body and it is very easy to maintain a straight stance. I never regard fitting the bike from the saddle to the ground standpoint but from the saddle to the pedals when they are in the lowest position, it's important that I can almost completely extend my leg.
Riding position (majority of the time) >>> stopping position (I can easily adjust for a couple of seconds).
My sister is 5"4 (and considerably younger than me, 23) and she could ride the Rhino (eu name for the rover). I thing she needs to lean to the bike when stopping, but it is fairly manageable, especially if one has previous cycling experience.