There is still plenty of time to get training however you need to be serious about it. The first 100 mile ride I do is in April. Which is 100 miles with about 6000 feet of climbing. And then just goes up from there until the Death Ride. If you don't have some kind of plan you should try to write down what you'll do for training and try to stick to it. As the time gets closer to July, I generally find I can't ride with friends and have to ride on my own. Either I am going longer or doing more climbing then other people as their goals are different. Which I think is one good thing about something like TNT, you get to train with people who have the same goals and keep you motivated. Maybe consider getting a coach, a coach can help too since someone else sets your training based on your goal(s) and you just need to follow it.

This year I didn't sign up for the Death Ride but I've signed up for Climb to Kaiser instead. However, at some point should you want to sell your ticket I'd buy it from you.