I use the TPT a lot since it passes 500m from where I live in South Manchester.
I've been west on it as far as Southport (and Liverpool on a different trip) and as far east as Penistone. As an aside, you might want to learn the correct pronounciation of Penistone.
Here are a few random observations:-
If the weather has been wet then it's likely that significant parts of the trail will either be muddy or covered in puddles. This is particularly true of the section around Lymm (I went along there on Sunday. See here for a brief report:-
http://yacf.co.uk/forum/index.php?topic=10.10935).
Some of the route is very rough; around Warrington, along parts of the Mersey in S. Manchester and the part mentioned earlier up from Woodhead.
For the climb from the Woodhead tunnels, I would actually take the road even though it's quite busy. The track across the top is a nightmare; you would need to be a very competent MTB rider to be able to ride the ramps/steps up from the road. If you're travelling east->west, then the road is good fun; a fast smooth downhill and you can get up to the speed of the trucks so there are very few overtakes by them. Just don't miss the turn............
Signposting around Warrington and in the Broadbottom triangle is rubbish.
Some of the inner-city sections can be covered in glass.
Friends of mine had stones thrown at them as they went around Speke.
The Child of Hale in Hale does good pub food and has reasonable beer. They don't mind if you fix punctures inside (I asked first).
A bit further along, the pub at Fiddler's Ferry also has good beer (better than the Child on my visits) but the food choice is limited (pies and crisps when I've been there).
About a mile off the trail, the Pickering Arms in Thelwall does good food and beer. Pricey though. They have an open fire and they turned the radiators back on for us when we visited; we were trying to dry our clothes.
There is a bridge to cross near Widnes and then a wooden staircase to carry your bike up (travelling west->east). This is extremely tiring, especially if you go back to help carry other bikes.
When I did a weekend ride to/from Liverpool it was very wet and muddy. My 300 mile old brake blocks were gone when I got back. Stopping was achieved by dragging my feet. Two of the others were similarly affected.
IMO, the ideal bike for the TPT has full mudguards, treaded tyres, hub gears and disc brakes. Narrow (drop ?) bars and a rack pack make it easier to get through the (many) bike gates.
Even if it had been dry for weeks, I wouldn't take a skinny tyred road bike unless it had a very supple frame; it would beat you up too much on the rough sections. YMMV.
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. We rode from &searchp=ids.srf&mapp=map.srf]Hadfield to &searchp=ids.srf&mapp=map.srf]Dunford Bridge.
And the longer bits that we did cycle? Again, no way I'd want to try riding a roadie - no way, definitely not, never. Not ever. Not till ............. well, you get the idea 
