La Spezia Tickets All Booked for August 2018??

Supposedly all train tickets should be loaded onto the ticket websites by now since it is within 4 months of departure date.

Wrong. The schedule is adjusted on June 10, and if everything goes normally, they might be posted by June 6. In the meantime, fear not, there will be trains and they probably will be on pretty much the same schedule as they are now. Regionali schedules and prices are negotiated with the provincial governments, and as there is taxpayer money involved, it always goes down to the wire.

Am I following this correctly? You are leaving Venice on the 13th, spending the night in Vernazza and on the 14th going to Florence, with a stop in Pisa.

Is the rest of your trip this frenetically paced?

What you really need is the transporter from the Starship Enterprise, not train tickets.

I am sure others will have responses more on point to the train ticket issue

Any chance you can adjust your schedule to spend 2 nights in Vernazza, to make getting there worth the effort?

Based on what you've written, you need some clarification on your plans. There are two principal routes from Venice to the Cinque Terre, either through Milan or through Florence. I normally choose to go through Florence. If you have a "stopover in Milan", you won't need to go to La Spezia since your train will go right past Vernazza on the way to La Spezia.

Your trip from Venice to the Cinque Terre is going to take the better part of a day (about six hours at least), so if you're leaving the C.T. on the 14th, that won't allow you much time to see much of anything. You'll basically only have your arrival evening (when you'll likely be tired) to look around, and that's it.

Not all ticket information for Regionale trains may be loaded on the websites yet. There is no price advantage with advance purchase tickets for Regionale trains, so there's really no reason to buy them now. You could easily buy them prior to boarding the train in Venice, and the cost would be the same. However with locally purchased Regionale tickets, you must validate (time & date stamp) these prior to boarding the train specified on the ticket. If you fail to do that, you'll face hefty fines which will be collected on the spot!

One of the quickest and easiest trips will be a departure from Venezia S. Lucia at 09:35, arriving Vernazza at 15:13 (time 5H:38M, 2 changes in Florence and La Spezia). If you decide on that solution, the only ticket that you can save money by pre-booking is the first segment from Venice to Florence via Freccia train. For the two Regionale segments, you can either buy on the day of travel OR purchase those online closer to your travel date. There's absolutely no reason to purchase those 4 months in advance.

Just to put a point on it. Regional trains never sell out. If no seat available you stand till one becomes available.