The truth is they didn't prepare very well for the voyage. In fact the voyage that they actually made had very little in common with the one that they had prepared for. They based their trip on a few bits of misinformation from sailors and other colonists. Most of the people that had been to the new world had been a lot farther south, around the area of Virginia and farther south. The sailors, just like today, would have told of the great things that they had seen, while leaving out the bad. Talk of waters teeming with fish, sunny weather, and friendly natives would have sounded great to the Pilgrims who were in search of a new home.
A few of the congregational leaders went back to England to get a charter to start a colony. While they were waiting for this to come through, the Dutch government offered them a chance to settle in the Hudson river area (which was closer to where they actually landed anyway). Like most European powers, the Dutch wanted as many settlers in the New World as possible to help carve out their own areas. We have to remember that compared to the relatively overcrowded conditions in Europe, the New World had an endless supply of timber, animals and farmland. Especially for a people from a small country like the Dutch did, the idea of that limitless supply of resources was a great lure.
A group of investors known as the Adventurers sent a representative by the name of Thomas Weston. They had secured a charter and offered to fund the trip in return for what seemed like a great deal. In return for the cost of the voyage the Pilgrims would work 4 days a week for the company. That would leave them 2 days to work on their own farms and of course the day of worship. As it turned out, the Adventurers were not all that they seemed. Once it was too late to back out, the deal changed and the the time they would have to work jumped to 6 days a week. This would leave them no time to create a life for themselves.
The problems didn't stop there. Of the two ships that were chartered for the trip, the Mayflower and the Speedwell, one of them was sabotaged. With the designs of the ships of the day, you could make a small change, that to a non sailor wouldn't notice. The Speedwell was refit with larger masts. To the Pilgrims this meant that there was more sail, which would mean a faster trip. The truth was, with the extra amount of sail, the mast would torque the timbers of the ship. As the ship got under way, it started to leak very badly. The ship was forced to turn back. On a side note, once the original masts were put back on, the Speedwell made many transatlantic trips with cargo very successfully. While rumors abound, there is not any solid proof as to who put the change of masts plan into play. The Dutch are a likely guess on it though.
Now the Pilgrims had only one ship to take them to America. They consolidated the supplies and had to cut down the number of passengers. It was decided that the strongest and healthiest should go on the first trip. It was going to be hard work to cut out a new life in the wilderness. The rest of the congregation would follow when they could. If they could, times would be hard on both sides of the Atlantic.
The original plan was to leave in the early spring of 1620. This would give them time to plant crops and collect food over the summer before winter set in. Several factors kept delaying them. It has been recently been found in documents that even the Dutch government had a hand in the delays. Because of these delays not only was it was already winter when they arrived but they had consumed close to half of their provisions before they ever even left English waters. It was not the best way to start a new life in the New World.
Although the difficulties may have seemed insurmountable, they persevered. They did it with their faith, strength as well with some help with the "savage natives".