1. Teach 6.270 robot design course; get some microcontroler boards
2. Build RC plane
3. Continuously develop manufacturing capability
4. Acquire flight experience (i.e. private pilot license, possibly USAF training)
5. Build (or buy) 2-way digital radio link
6. Make semi-autonomous/robot controler for RC plane
7. Build RC helicopter
8. Make semi-autonomous/robot controler for helicopter
9. Build very small liquid fueled rocket engines
10. Build RC helicopter w/ blade-tip rocket engines
11. Make autonomous/robot controler for rocket helicopter
12. Modify rocket helicopter for high-altitude autonomous flight (w/ downlink)
13. Convert to minimum-scale, unmanned orbital ROTON concept.
14. Build ultralight for experience w/ manned flight.
15. Build larger scale, manned version of ROTON concept.

The first two steps have been completed.
Steps three and four are in-progress.

This plan is very skills-oriented. Each step is designed to help me acquire experiences, skills, or knowledge. The great thing about this plan is that I actually get to build and fly things.

It's cheaper to design something that works than to build a test and make it work.
But...
It's cheaper to build a test and make it work than to design something that doesn't work later.