MFL.
Sorry, we were gone most of the day and I didn't see your "slow speed" question. YES, it will go any variable speed you want it to go. Just twist the speed section of the right hand handlebar grip as far as the speed you want to travel at. <1 MPH thru 17 MPH. Totally variable and doesn't NOT have any preset speeds in notches. Tipping is something she will not have to worry about at all nor tipping over backwards.
There must be a Camping World somewhere near you as they are all around so you won't have to pay any extra for the shipping. Camping World has sales from time to time and also you save more by being a President's Club Member which is $20/yr I think. We've been PC members since 198? when it was first offered and we've saved well over a thousand dollars by being a PC member. Also CW had sent us a $50 voucher to be used on one item of X min cost in the mail and we used that too so all in all we paid a lot less the $1600 for 2 Zappy's including the 6% Michigan sales tax. I won't print the exact price we paid as Marcus might not like that since prices vary from time to time and maybe also in various areas/regions. You'll just have to get the best price you can whereever.
I don't know where you live in the Midwest so I wouldn't know where the closest CW is to you. Regardless, $132 just for shipping seems very high as the Zappy would have to go by truck due to weight. I think they will come from Bowling Green, KY in the Midwest at least for Midwest sales. Call ahead to a CW and make sure they have a Zappy in stock and if they have one on the showroom floor for demo so your wife can tryout as that's the best way. Grand Rapids CW let us take the showroom demo Zappy out in the parking lot and we gave it a real good tryout before deciding it was right for us. Bought 2 and it sure is!