I don't know where you ride and why, but you, unfortunately, fit the stereotype fearful female bike rider. You should not go out in traffic fearing anything! Dismounting and remounting are trivial aspects of bike riding and a ride of any length requires several such dismounts and remounts. Why wouldn't you make it back upright? Why would you be not upright in the first place? When you dismount you move forward off the seat and drop down into the space between you and the handlebars. The bike is tilted minimally, if at all. I once had a seatpost break on a long ride on our tandem. We found a machine shop and they were able to pull the broken part out of the frame and we re-inserted what was left and completed the ride. I was several inches lower than usual but it really wasn't any big deal. If you have to lower your seat a LOT until you get more comfortable, just do it. Better that than that you are nervously riding around in traffic. This just does not sound like a good situation going on in your world. Also, there shouldn't be the need to resort to a cruiser style of bike just to get a more "step through" kind of frame. There are mixtes, step throughs, and even regular old 'sloping top tube' type bikes that fit many women riders. You appear to want a road bike and road bike type performance. You cannot force a cruiser into that role. I hope you sort all this out. The country needs more cyclists.