There are a few question marks on this leg of the trip, what with arranging visas and all.  I've tried to plan this on the most-likely-scenario.  Examining tea-leaves and tarot cards, this does seem to be the likely plan:

Week 1
Istanbul, business and pleasure.
Visas - I'll hopefully already have the Iran visa in the bag by the time I start this trip, and possibly the Uzbekistan visa.  However, I'll have to apply for the Turkmenistan visa but how long will I get ? Ten days (very unlikely) will allow traversing the country completely by bicycle, with sightseeing included.  Any less and I'll have to compromise and use .. phah! .. a bus part of the way. Three days and I won't get a chance for sightseeing nor cycling - straight through to the next border. An alternative is to get a tourist visa through a tourist agency, which requires paying for an escort for each day of my stay, and a car !  I guess I could think of it as my "support vehicle" though as it will probably be a Lada the question arises of who's supporting who. Current feeling is to risk it with the transit visa... we'll see.
    Well, while I'm waiting for the visas to come through, I'll make sure to tick off the sights, and maybe even a short trip to Cappadocia.  There's an outside chance that my brother may visit for a few days, also acting as a spare-tire-and-tube mule.  However, his definition of a holiday (5-star hotels, pool-side cocktails, ..) does vary somewhat from mine...

Week 2
Providing the required visas have come through, set off again - but with a heavy heart, and a modicum of shame... by bus. Depending on the amount of time I have left, get off somewhere before the Iran visa, and cycle across to Maku, thereby pretending that I've cycled the entire breadth of Turkey! Ask me no questions, I'll tell you no lies...

Week 3
Iran: warm friendly people, excellent roads, rich rich history... what more could a cyclist ask for ? Only that Bush reign in his imperial ambitions.  I'm looking forward to Iran, though the full length trousers and long-sleeve shirts may get a bit old after the first week. My first week here should see me cycling to Tabriz, including a day trip to Kandovan if I didn't make Turkey's Cappadocia, and then heading down to the Caspian sea coast.  By now I will have resigned myself that there are mountains in this world, and some of them are in my way.

Week 4
A ride up through mist-draped mountain valleys to the beautiful village of Masuleh, and just as you thought Steve had mended his unsavoury bus-riding ways, hop on a bus to Tehran.  Hey, I'm on a time-limit here to the Turkmenistan border!  Spend a few days in Tehran before cycling (downhill, I'm hoping) to Sari and and Gorgon.

Week 5
Take a couple days to rest up and wander around the mosques and bazaars of Sari and Gorgon, before sheepishly boarding a bus (oh Jeez, not another!) to Quchan.  Next morning, from there cycle across the border into Turkmenistan and onto the capital Ashgabat.  A long day, and still unsure of what awaits me in Turkmenistan...

The fortune-teller lied - I didn't get my Iran visa, so maybe the plan will progress something like this instead...

Weeks 2 to 4
A ferry or a bus to eastern Turkey, and then cycle across the border to Georgia.  Pass the ancient cave city of Vardzia, and arrive in Tbilisi, the most attractive capital of the Caucasus apparently (but don't go out at night). A couple days R&R and then head south into Azerbaijan and the mountains, passing mountain retreats like Saki and Lahic, ending up at the capital (and port) Baku for yet more R&R. There's not a great deal of tourist infrastructure yet in these parts so a little unsure of where to stay and what to do...

Week 5
Board a boat to take me across the Caspian see to Turkmenbashi, Turkmenistan.  By a combination of car and bike, make it across the hottest part of the Karakum desert (mirages have been guaranteed!) to Ashgargat, from where (see next section) I'll be hoping to team up with a couple other cyclists to ride to Uzbekistan...