Also, a little applied psychology: I know all too well how it feels to be saying "I have to do C, but first B has to be done, but before B can be started, there's A...". That is backtracking phrasing designed to stress a person out! You can be kinder to yourself by choosing the A-B-C phrasing of natural progression.
When you put your trailer on the land, you'll have a waterproof, windproof, cleanable and presumably heatable tent to camp from, that's off the ground so it won't be damp and rocky. Could even be homey. The weather will be getting warmer as the season progresses, and you can watch your land getting greener and leafier and more beautiful, with no effort from you; and you can expand your living space outside, perhaps with pleasant al fresco dining and grilling. Water is nearby, an odourless compost toilet serves you, and at worst a hillbilly sink drain bucket for selective watering. Voila, the essentials, and maybe even an abundance of the necessities, and some rustic luxury, if you look at it that way.
You guys have over a month to clear a path for the power, and for the building spot. At the same time that you're doing that, you are by default also cutting fence poles, and firewood for future winters, giving yourself a head start on those tasks that you'll thank yourselves for. A lot can be done in a month; and living onsite, there won't be any commute to eat up time. Evenings can be spent elaborating on and delighting in your house plans--not as a "have to" activity, but as a "want to".
Come the end of May, when the frost is out of the ground and the load limits are lifted, you'll be ready to buckle down on the house, full of enthusiasm, with your plans reviewed and refined.
All will be well. Just don't expect a fully functional permaculture homestead by the end of 2017.
(And if somehow you pull that off, I DON'T want to hear about it! :greenface: )