I've logged about 10 full games of solitaire Agricola now, and am having a lot of fun. I cracked open what appeared to be the "E" deck (which stands for "beginner" for some reason), and played about 6 games. I discovered quite a few more "E" cards in the shrink-wrapped pack of "I" cards, and have played 4 more.

So far my scores in the first four games are: 60, 63, 70, and now 76. I kept the Carpenter from the first game, Chief from the second game, Plow Maker from the third, and will be keeping Seasonal worker from the fourth.
What is fascinating is the different shortages and challenges you are faced with in the game as you progress. Food is scarce in game 1, then stone begins to become an issue. Depending on what occupations come up, you may have problems finding reed or clay - or at least "over-spending" for them and facing a lower score.
Reading some posts on the 'geek, I've taken a much more critical eye on the benefits (or lack) from different minor improvements and occupations. For example, Wood Cutter sounds like a good deal (+1 wood each time you pull wood) - but when you count the fact that you are only pulling wood 4 times in a game, and you must spend a action +1 food to actually place the Wood Cutter - you might as well just pull wood a fifth time and save yourself the 1 food!
Plow Maker is an awesome occupation, as it clearly saves you 1 extra move, usually two. You can plow three times and place 6 fields, saving you 2 full actions for the cost of 4 food (1 for the placement of the Plow Maker, and 1 each for the 3 extra fields you generate). That is a clear winner, and so much better than Mushroom Collector, Clay Mixer, Hedge Keeper, etc.
An exception is Stone Carrier, which might pay you out only 2 stone for the cost of an action and 1 food - this is probably well worth it if you plan on a high score, as stone is the ticket to Well, Stone Oven, Pottery and all the other "bonus" Major Improvements.
I did not do very well in my first game of Agricola with Kevin, but after 10 solo games I think I will be very competitive the next time we square off in this one...