Train however is best for you. Try training in different ways too. For example, I found doing weekday rides short but more intense by myself was easier because 1) it was in the very early hours of the morning before my family was up and 2) it allowed me to focus on particular things I wanted to strengthen like hill climbing or sprinting.

But long rides are very hard by myself. My mind starts to wonder and/or I look at people's pretty yard art and just slow down way too much for my goals.

The year I did the 80 mile El Tour de Tucson, I had only been riding one year and it was with a group of ladies who like to take a more leisure pace. So what I did was ride out to meet with them. I would start my ride at about 10 miles away from them. Those first miles I would push a little to get there on time. Then ride any where from 15-25 miles with them and then ride back home. Again giving a little push. Sometimes even making the return route longer than the start route, depending on the heat in Tucson.

This method gave me something to look forward to and kept me interested and on pace.

The next year I wanted to train for 109 mile ETT but wanted to push a little more. I didn't ride with them since I needed even more mileage and the weather was so hot so time was not on my side. Again I did my weekly rides alone (mostly because of schedule) but the long rides with a club. Somehow always found someone who was almost as slow as me so I was forced to push myself a little to keep up.

I did end up doing one long ride (about 70 miles) by myself but I had done enough with other people that I looked at it as an exception and turned it into an excercise in concentration.

And like people mentioned here, on the long rides my DH was home (ok had to be, he was on kid duty) had plenty of water and snacks in my Camelbak, knew my route very well, bike map and if I had to go on busy streets, would try to route it in such a way that it was earliest in the morning. Also, Sunday mornings are much quieter and stay quiet longer than Saturdays.

Good luck!