I would create (and not just talk about doing it like some people are at the moment) a HYPER TUBE which you sit in and it transports you extremely fast a bit like a metro system BUT in a tube.
You could go to America in minutes, and why not extend it into space?!
Also imagine circling the Earth but under the sea in the HYPER TUBE and seeing all the fish, travelling between the artic and Australasia and perhaps bumping into some submarines!?
As it is a vacuum it would be very very efficient as there is no resistance and we could stop for some actual Chinese food!
That’s my vision and what I would like to do- create my own HYPER TUBE loop system. I would design, manufacture, create the software, link it all to the internet and then advise from my own engineering consultancy 😀