In all honesty, especially since you're new and likely not going to be racing in events that last longer than a few hours at most as I'm assuming you're targeting criteriums... base miles are a waste. That is unless you've got more than 20 hours a week to dedicate toward bike specific training. If you do, go ahead and put in some base miles but otherwise substitute that for tempo, interval, sprint/fartlek, and group rides. Throw on some base miles if you start to feel tired. There's a lot of discussion about this, search something like time crunched cyclist and you'll see a ton of discussion about it on here or other boards.