I'm another vote to switching to one nap. It seems like what works for most parents/kids is to push that first nap later (to after lunch around noon) and have that be the only nap of the day. For my kids they both seemed to be tired in the morning, but then they would fight the afternoon nap and get tired later, like your guy, and be sleep at 4 or 5 pm, which is just too late! We do bedtime at 8 pm, which means that we start a bath at 7, wash (and calm) in the bath, brush teeth, read books and then get into bed with the lights out. So my suggestion is to plan more outings so that he's occupied (read: not cranky) around his usual morning nap time. Indoor play parks are good. You might be sad about losing some free time during the day, but you'll be soooo happy that you're not staying up until 1 am putting him to bed!