I've been riding and racing just a bit longer than that.
"Base" is a term from periodization. Friel's book says flat out that the body isn't ready for periodization until it has a certain fitness level, usually achieved over the course of two or three seasons. True base fitness is built up over the period of years; it's not done in a mere few months. The "base" that everyone talks about is simply a period of time in the periodization schedule where the already relatively fit rider rides long, relatively slow, miles to prepare the body for more intense training later.
The new rider just needs to get hours on the bike, both at low intensity on long rides to learn what it's like to be in the saddle for hours at a time, and at very very high intensity during intervals (but skip the short 30 sec-3 minute anaerobic intervals at this time; again, on Friel's advice - those just will lead to injuries and burnout in newer racers) to know what it's like to go hard. The new rider should start the training plan in December and learn how to ride 2x20 minute intervals twice a week at maximum sustained power over both intervals (IOW, both intervals are done at the same power level). If you don't have a powermeter, use a trainer, put a rear wheel speed sensor on your bike, and use speed as your guide (speed has a direct relationship to power on a trainer). These long intervals are very important for the new racer. Most recreational riders have endurance, but they lack the experience pushing the limits of their body. Intervals give them this experience.
I think of my training like the process of sharpening a knife. A recreational rider (I was one once, obviously) is a metal blank. To transition to a racer and start putting an edge to the metal blank, you start out with a course file (hours on the bike and threshold intervals). After you have an outline of an edge (end of your first full season of racing), you move onto a finer file and the course stone; that is, you start integrating the rough outline of a periodization plan. Finally you have an edge and you start the normal (yearly) sharpening progression of medium stone to fine stone to sharpening steel: full periodization. Periodization is the seasonal sharpening of an already sharp knife - you start the season with a medium stone and work your way up to a sharpening steel just before your peak. Starting your racing career with a course file and progressing deliberately to a periodization cycle will put an even, well shaped edge on the blade that will last over years of periodized sharpening cycles. Skipping over the early parts will make the edge uneven and rounded; you can put an edge on it every year, but it won't be consistent over the whole blade, it won't be as sharp as it could be, and it'll dull quickly with use.
And now I've stretched the analogy as far as it goes
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Anyway, this is what has worked for me over the last three years. I started by just doing a lot of 2x20min intervals, along with a lot of just plain riding during the winter for the first couple years. The first year, the intervals schedule was not terribly steady; it got better in the second year. This last season (my third season) was my best; I did it with only the rough form of periodization with a winter of pure base, threshold intervals in the spring, and then spent the rest of the season racing my way into a fairly high level of fitness. I raced everything from hilly road races to time trials to crits to track. I gained tremendous insight into my strengths and weaknesses this year. There was never a time when I burned out; if I started to feel ragged, I took 4 or 5 days off and my attitude was looking up again with no loss of fitness. Next year will include more aspects of periodization and hopefully more results. I'm an amateur; I got into this sport too late in life to become anything but that, so to me, the yearly progression of training and fitness is part of the appeal of bike racing.