Can you come up with an offline desktop mode. Mobirise have such feature. Appy Pie has the best feature and can do more by having an offline app builder.

I know the feeling... I am still trying to get satellite internet to my house, so I built my app in a friend’s backyard, at the library, in parks, sitting in my car and on the roof (only place I get a signal). At least it all saved quickly and easily. It would be nice to have offline, but I understand why that might never happen. I can’t code, but I do imagine making an app the “old” way would be even harder without internet... it was nice knowing it was “saved out-there” and I could pick it up wherever I happened to be, even if it was on someone else’s computer. I wouldn’t even have contemplated trying to make an app if someone awesome hadn’t introduced me to AppyPie.

I doubt they will offer an 'off line' version as that is how they control the product. That said, you should be able to access your app on your cell phone.