If you are worried about the floor being hot you can put Dynamat on the firewall. It will cut down on tire/road noise.
As far as bed liner goes. There are a lot of good brands. Some brands you can order in various colors, some you have to put uv protector over. If you want a smooth texture I would recommend having it sprayed on. If you are going to do it yourself, test it out on a piece of sheet metal first to make sure that you get the texture that you want. You can do a lot with different rollers and thicknesses of the bed liner. At work we have been having Line-X sprayed on. It is one of the better ones that I have seen over the years, It has a fairly smooth texture when done. For other equipment and the occasional repair I use this Dupli-Color® Bed Armor™ BAA2010 - Truck Bed Coating | O'Reilly Auto Parts
It works well, has a nice texture when it dries.
Best of luck
ASE Master Auto Tech