I just thought I would drop a field report after visting Maccu Pichu.
Having mined the guide's brains on this it seems that if you want to get to M-P for the morning light this would mean staying at Agua Calientes and catching the first bus at 5am. Getting there early is very popular in itself so he suggested getting to the bus stop an hour before - it sounds like a mug of coca tea and a good book are in order. And if you want to get up Huayana Picchu you need to book ahead (he said 2 months) because there is a strict limit of 500 people split between 2 shifts and it takes as little as 40mins at a fast walk (up that slope...
!!) but usually 1-1.5h.
Depending on who you talk to, there is a theoretical limit of 2,000 people per day allowed into the site but numbers can top 5,000 (even apparently 7,000) on a 'bad' day. When we flew into Lima we saw many operators offering trips and similarly at the much smaller Cusco airport so I can see where the problems come in. But it seems that though booking at the last minute is certainly not an issue, availability may be.
I saw no-one using tripods but then again neither did I see any bag searches so my guess is that when you actually walk into the site try and keep gear discrete, packing a tripod and physically big lenses in your bag if they will fit (or strapped to the side covered by a rain cover).
At the train station there are signs pretty much like the ones you see in airports indicating baggage about 15"x12"x8" (I think) with weight limit of 5kg. But there were no bag checks (contents, size or weight) even though some were clearly over those sizes so at least make it look like it weighs about 5kg even though you shoulder may be killing you
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I have no idea if my experience above is anything to do with it being off-season (fewer people, less strict), but seating on buses and trains is all pre-booked and we had no people strap-hanging which means that space is not a limiting factor in what you would be able to take on board (unlike cram-packed budget airlines).
The tour company we booked with created a tailor-made itinerary for us and I asked the manager if they could do the sort of thing you are thinking about and he said no problem so drop them a line and start discussing it. We have found them to be excellent and very helpful and if you have time their 'Sacred Valley Tour' is worth it.
Here is another link I came across that may be helpful regards photos at Machu Picchu:
http://www.meaningfultraveler.com/wp/wp-content/uploads/2010/10/How-to-Photograph-Machu-Picchu.pdfWhile I am typing away I thought I may as well add a bit of 'tour guide' stuff: I don't know how much photography you have done at altitude but although M-P is 'only' 2,400m (8,000 feet) it seems to make the sun fierce and I burnt quicker today than I have in many a year, including the tropics - I guess it is the dry air we had the last couple of days (says he listening to the rain teeming down in Cusco) so sunblock, hat and sun screen are essential.
There are no toilets past the entrance so use the ones just before the gate (mercifully very clean and well maintained) and there are no refreshment stalls either so make sure you have water at least (there is a café just before the gate).
Money: Outside the big cities US Dollars are not easy to use and you get a poor exchange rate if you try and pay with dollars. The ATMs seem to dispense only 50 or 100 Soles notes which can be hard to spend at small stalls - partly because they often don't have the change to give to you and partly because they don't like taking them because they also find them hard to spend. So start breaking into the big notes as soon as possible.
People photography: I am finding this harder to judge as time goes on not because of any adverse response but more and more people seem to expect to be paid, especially the less well off. But this is one situation where it helps to have coins or small notes. I try and avoid paying kids for taking their picture especially if they are the ones coming to me ask to take their picture, though sometimes an opportunity is too good to miss and 1-2 soles seems to be the going rate. But with adults I much prefer to 'exchange' things for a picture: if someone asks me to buy one of their wares I show interest in a low-value item like a wrist band (about 1soler = 30US cents) and gesture that I will buy one if I can take his/her picture. They always agree so I end up with a pocketful of cheap wrist bands but they have a sale and I have a portrait - a good exchange I think especially as I am usually too self-conscious to ask someone to post for me off the cuff and this offers a way to bring the subject up.
As for food: guinea pig ('cuy' in local language') tastes like dark meat of chicken (but there is pitifully little meat on the beasts) and alpaca is very lean and tastes like venison. And this is no place full-bore vegetarians.
I hope this helps but if you have any other questions let me know.
