There is no question that one month is plenty of time to recover from an event between 3 and 4 hours. This is assuming that you will take enough down time after the event.

The only way you would be tired going into the next event from a maximal effort at the first one would be overtraining in the weeks between the events. Making sure you take a lot of down time following a race which you fill with recovery, massage and good food will set you up for another big effort.

Racing is an opportunity to test your limits. I say go as hard as you can and do your best! You will get a lot of benefit from a hard race. It is very difficult to push yourself that hard in training, so each subsequent race will then become and feel much better.