I'm trying to reserve our train tickets for the major parts of our upcoming trip online and am getting frustrated with the Trenitalia website. For instance, when I'm on the reservation page it gives me four options:

-Ticketless with payment receipt via email
-Ticketless with payment receipt on board
-Self service not available at the departure station
-Home delivery

Only it won't let me check either of the ticketless boxes. So my choices are self-service not available at this departure station and home delivery. I think its too late to choose home delivery, but I'm confused what the third option means. Any help?

I guess the other larger question is should I bother to reserve our tickets ahead of time or should we have any problem buying them when we get there? The major legs of the journey we will be doing on train will be on May 22, May 28, June 6, and June 13th which don't coincide with any major holidays to my knowledge.

First, there is absolutely no advantage to early purchase other than possible discounts. Trains rarely sell out. Since you didn't give your schedule,it is hard to evaluate your problem. Is it possible that you are selecting trains that do not require a seat reservation and, therefore, is not available for advance purchase.

Trenitalia won't deliver to the US (or other countries outside of Europe).

What are the routes you are trying to book? June 13th schedules (summer isn't loaded yet)are not online yet.

I was trying to book a route from Gorizia Centrale to Florence on May 22, leaving at 9:40 am. Two adults. First class. And it sounds like we don't need a ticket for baby.

The website says trains:
Regionale Veloc 2452 from Gorizia to Ve. Mestre
and
ES Italia AV 9413 FRECCIARGENTO from Ve. Mestre to Florence

R trains don't have reserved seats so no need to book in advance for those and the first part of the Gorizia/Florence route is on an R train. It's also telling you there are no self service kiosks at that station to print your ticket. Plan on purchasing your Gorizia to Ve Mestre at the station (or you can purchase at a travel agent/tobacco shop with the Trenitalia logo - be sure to validate ticket in yello machine before boarding). You should then be able to book the Ve Mestre/Florence portion online and you will be able to select ticketless with payment receipt via e-mail. ES tickets don't need to be validated track-side as they are for a specific seat on a specific train.

The Italian Railpass, contrary to Fodorites opinions, can surprisingly be cost effective if taking four train trips.