We all love races but how do you adjust your plan if it didn't include the bunch of cool ones you want to add to your season in the first place?
Step 1: Read this blog on How Peaking Works and give the new races a priority designation. Next follow the guidelines below.
Priority A: at most you are adding no more than one of these to the Marji plan. Ideally none at all and you are fully focused on Marji (did anyone mention that it's one hell of a race?) But if you have added one more A race then you are going to have to accept a bit of a dent in your overall training. All A races are going to need a 2 week taper, and most likely at least a week recovery (if it's a short race <4 hours) and possibly a full 2 weeks not getting any fitter if it's something big and bad (200 miles / 24 hour solo) That's a month less fitness to get your through Marji so don't take this decision lightly. Still want another A? Plan it in, go backwards 3 weeks and look at what will become the last big week before tapering, use this week as the template. Week 1 of the taper (2 weeks out from the A race) knock one third the duration (or number of blocks or intervals) from the Monday to Friday sessions, half the duration on Saturday and Sunday. The week before the new A race... tricky. Either use the template week and half the Monday to Friday sessions. Copy the tune up from the day before Marji and add put this as the session the day before your race. Make the day 2 days before your race a rest day. Now look at it from a "how hard are these sessions and how do they normally make me feel?" point of veiw and if it looks like too much delete some of the taper days and add extra rest days. A little intensity is good ina taper, too much volume rarely ever is. After the race you are going to need to schedule some rest, but you don't want to slack off for too long. If it's a massive ace then all bets are off as to how long this might take. Some athletes can recover in less than a week, others need 3-4 weeks to recover the first time they do something epic, and then might still be sub-par for another month.
Priority B. These are like a lesser A. I'd cut and paste the week leading up to Marji and use this a a template. Apply the same common sense filter as above and decide if it requires a bit more rest. After the race factor in a couple of rest days and then get back to work.
Priority C. Just sub these for a session. They shouldn't be epics. If they are you are kidding yourself (I mean that in the kindest way) They should be fun races, that are fairly short (typically <2 hour XCO style) or slightly longer social events ridden at party pace (and usually with slower friends) Just swap them for a training session, train right up to them, and get back into training pronto afterwards.