Amanda,
I'd also like to add congratulations!
Could you indicate if the 10-day time frame includes your flight day to Italy and the flight home?
As you're "comfortable travelling in Europe", I'm not sure that Europe Through The Back Door will be much help for you. However, I would suggest packing along a copy of the Italy 2010 Guidebook, as it contains a lot of information that will be useful, including lodging suggestions, restaurants, transportation, Museum opening & closing times, etc.
For the sake of efficiency (and assuming you haven't yet bought your airline tickets), using open-jaw flights would be the best idea. You could fly inbound to Rome / FCO and outbound from Venice / VCE.
For the trip from Rome to the CT, there's a direct train from Termini to La Spezia, with a travel time as short as 3H:41M. When you buy your ticket, be sure to specify the village you'll be staying in as the destination, so that you don't have to buy a ticket for the local train when you arrive in La Spezia.
I'm not sure if it will be open in mid-October, but one B&B you might consider is This One in Manarola. It will be a bit of a "splurge" but would be perfect considering the occasion. Send them an E-mail if you're interested. That time of year will be fairly "quiet" in the CT, so you'll probably find a better range of accommodations in Monterosso.
Regarding "recommendations on places to stay/see/dine? ", it would help to have some idea on your interests and what types of things you're most interested in seeing? There are lots of sightseeing possibilities in Rome and Venice, but the "usual" activity in the CT is just relaxing and perhaps hiking the trails between the five villages (depending on the weather, you may have to limit yourself to only the famed Via del'Amore between Manarola and Riomaggiore). The Guidebook covers all the options for that area.
Happy travels!