Since this thread was started in reference to my planned trip,I have read every post...most of which say more about the poster than the problem.
Now, let me add my small voice to the proceedings.
It occurs to me that there are two distinct camps in this discussion: 1. Those that prepare for almost anything that could go wrong by bringing the tools and parts necessary to fix almost anything, and 2. Those that believe their car will do fine because they have done proper maintenance prior to starting out and have enough trouble free miles under their belts to predict the trip will be successful. I am in that camp.
Besides, as has been noted by MBell, virtually any town has an auto supply store for things like fluids, hoses and spark plugs and wires so carrying them is just sacrificing lightness.
Therefore, I am taking the three most important things to solve EVERY potential problem that might occur and they will actually fit in the seatback pocket of the Plus 2, requiring ZERO boot space. The membership roster to which Tony Vaccaro referred (which is 8 1/2" X 11" and 1/4" thick) lists every Lotus Limited member who is willing to offer assistance, tools, help, lodging or even a trailer for recovery. This is the single most peace of mind device I will have with me.
The other two are merely secondary but will solve any problem that comes up and they are: A cell phone and a high limit credit card. Questions?