Not sure what the fuel prices are like in your neck of the woods, but if they are anything like here, this could make for a tough choice.
I would go with either Diesel or Propane.
The Transfer switch will be the most expensive item and the hardest to install.
Provided that the Genset gives 240VAC output you will be OK.
I'd get in contact with the Power company before you do anything though, they will have rules regarding inter-connecting with thier system to make sure that there is no way that a Back-feed can happen.
Manual start is the simplest and to a degree the safer option,as if there is a remote start switch, you have to have a padlock-able switch on the Genset itself, that prevents the Genset from starting while it is being worked upon, unless the remote switch can be locked out.
I agree with Alan though, Tech Reps are your best source of info/help.
Often these guys are not salesmen, but ex-Electricians that sought to move into that side of the field.
We have an ABB rep here and he is a gold-mine of information, you don't get a sales pitch either, just knowledgeable help.
You just have to ask.