Since you NEED to get them in, here is how I would do it. Plant them deep if you can, so there isn't as much exposed. Also the stem will root too for a better root system.
If you are going to cage them do it now. Add several old soda bottles or milk jugs full of water around the plant, inside of the cage. That will provide heat storage. Wrap the cage sides with clear plastic. You are making a mini greenhouse but without a top. The plastic will warm the soil and water for a "heat sink". But without a top, it won't overheat the plants.
On nites it will get below 40*, put something over the top at nite. A blanket or large garbage bag or ?? Be sure to take it off again in the morning.
This is something I adapted from an article in Organic Gardening from way back when it was the small size. Personally I do too big of a market garden to do it that way. But my neighbor did it with about 30 plants every year. He planted 3-4 weeks before our safe frost date. He had the plastic around the big woven wire type cages stabilized with a fence post. He would leave it on for about 6 weeks +- depending on the weather. By the time he took the plastic off, the plants were growing out the top of the cages.
Here is a visual page on my web site of this idea.
http://knapps-fresh-vegies.netfirms.com/tips.html
Good luck with your plants,
Carol