okay, I think, that eventually when you can make missions and stuff, there should be 3 modes.
flyby (simple)
Semi-Manual (more what people will want)
Manual
Flyby mode has a check list of all the objects in the system, and a drop down for which object to start it from.
Semi-Manual mode will have
Start From: [ drop down ]
Flyby checklist of objects to flyby
Orbital bodies [ drop down ] (1)
Orbital body checklist (2)
1. In here, it asks you how many objects you want your probe to orbit
2. Here you choose which objects those are and the order. And how long for each object.
With this data, US should calculate the next time a reasonable amount of time will take to execute this, and what amount of time it would take if you did it at the current time. It would then show the path and what time it was at closest point to the objects.
Manual mode will have
Thrust 1 [time] [force]
Thrust end [time] [force]
+ (add another thrust)
This would be really simple to make, but sadly, then the users would have to estimate or calculate themselves everything they want to do, this would be for more advanced users...
---------------------------
Combined with the "multiplayer" you could create a system, then people choose their own planets, and make missions to the other planets (or even stars)...