Basically, you need to develop a large number of encounter tables for various conditions, and decide if your PC can have additional hirelings to assist. The supplements that you will need are 1001 Characters, Animal Encounters, Citizens of the Imperium, 76 Patrons, and Veterans to give you some encounter lists to work from to generate your specific encounter table. Then determine what world or worlds you are going to be adventuring in, and what character class fits you the best. Once you know what world or worlds you are operating in, you can generate encounter tables for those worlds from the above supplements, without adding your own biases. That is if you wish to generate the entire set up yourself.
Some of the published adventures lend themselves to solitaire play, one being the Chamax Plague, as the Chamax can be run as automated attackers, and there is a range of situations to deal with. Just assume that you are one of the off-world commanders of local units, and have at it with one of the characters provided.
I used this system while playing Basic Blue Book D&D at Walter Reed Army Medical Center (which no longer exists) when I was spending several months there in a hospital bed. I have played some Traveller the same way. You have to be honest with the die roll though. If it says that you are in trouble, you are, and if you are killed, you are dead.
Also, using some form of miniatures helps too.