Hi Rita!
What a great way to celebrate your anniversary -- and the planning can while away the snowbound months in Saskatchewan! The list of questions sounds as if you want someone to plan out your entire trip for u -- and I'm sure that's not what you really want from us, because we're helpers, not professional travel agents. How about doing some research yourself, then coming to us for opinions on specifics? Here's what I suggest:
• GUIDEBOOKS vs WEBSITES - Websites are great for color photos -- but NOT for full information. Trying to get all your info from the internet is like trying to drink from a fire hose; you get drowned in data, but still are thirsty. Guides are invaluable in helping u focus, & the best (candid) ones help you avoid the "hype" that internet sources may have. You're going to spend many, many thousands on this dream trip... why not spend just a few loonies to get honest advice??? U can get used copies from Amazon cheep-cheep; & not necessary to get latest editions. You won't use these for hotel & dining prices, but for general highlights & itinerary advice & those don't change. I've done 11 Greece trips & have shelves of guidebooks, but my overall favorite is Rough GUide to Greece. VERY detailed/candid, good maps, doesn't waste too much space for color pix. A bonus: u can (carefully) pull out relevant sections (Cyclades, Athens, etc), bind spines w. duct tape and voila! instant pocket guidettes! If u have a good publlic library, browse thru EYEWITNESS: the Greek Isles and GREEK ISLAND HOPPING ... the first for its succinct visuals on highlights, the 2nd for realistic itineraries via ferry. Rick's Greece book is more limited but good on Athens and Argolid area D-I-Y advice.
• TIMING -- Good for you, avoiding the cram-jammed hi season: the best months are May-June & Sept. If u are going a full month, I would suggest doing Sept 1 - 30 or Sept 10- Oct 10 rather than later because many Isles are "closing down" by then... weather still good, but many proprietors shuttering to move to mainland. Big isles like Crete of course are active year-round. Still, transport cuts back sharply by October -- Greece does not have the long "shoulder seasons" as Italy.
• WHICH ISLES -- Many people are misled by Cruise ballyhoo. Those monster-ships are limited to deep-water ports, so they hype as "must-sees" the only places they can go: Santorini, Mykonos, Heraklion, Rhodes, Patmos. Santorini is a must-see for newbies, others are options. And they never mention Cycladic jewels like Milos, SIfnos, Naxos, Folegandros.
•TRAVEL OPTIONS & SEQUENCE -- Transport is KEY to a great trip; countless people come to forums weeping about nonreturnable hotel deposits on islands they cannot reach! A Tested strategy: Land in Athens -- fly ASAP to your farthest island destination -- ferry-hop your way back -- sightsee Athens at the end. This ferry chart http://www.greeceathensaegeaninfo.com/ferry-info-greece/greek-islands-ferry-chart.htm -- altho outdated & for high season -- but shows most-usual ferry routes. Get to know THIS website http://www.gtp.gr/RoutesForm.asp -- If you leave the Month & date at "any" you'll see all available sailings... if you specify month but leave date at "any" u will see all of Sept. for example. It's the first site to show Fall 2015 listings, but they wont be up for quite awhile. THIS site http://www.openseas.gr/en/index.html has a magic "rollback" feature -- you can put calendar back to Sept 2014 & see what ferry routes were offered then; they're much the same year to year, so it's a useful planning guide.
• TURKEY? I'm not a huge fan, being a Graecophile; again, do homework, ponder cultural interests, before deciding.
Have fun planning... the more you prepare, the better we can help you... otherwise, you're just going to get fragmented advice based on a particular person's enthusiasms.