No problem with your questions. If at anytime you want a more detailed description drop me a PM.
I think you can be fairly safe with painting Adobe neutral shades or even plain white as it will look ok for any theatre. My only observation is sometimes the middle eastern ones have a domed roof which would necessitate a different design, but other than that go with whatever you like. After all its only representational and its a look you are aiming for. We are making stylised models, not architectural ones.
The main thing to consider is making sure the baseboards and the terrain that you play on matches your choice of colours on the buildings as invariably the buildings are built from mud bricks cut from the ground. So I always paint the whole model including the base in the same colour and try to use terrain boards/cloth that are the same or very similar. I think that helps to anchor the buildings to the terrain and make it look natural.
I use a sand colour as the initial baseocat/undercoat by Humbrol but recently found a good colour match at my local Homebase(DIY store)
I then wash a raw umber brown mix from a tube of artists acrylic paint around the bottom of the building where the walls touch the ground, to represent dirt, dampness etc.
Next I take GW Bleached bone and use a fairly wet brush and liberally work the paint in leaving the brown wash along the bottom and some of the sand shade showing through finishing with the bone colour covering all the sand shade at the top/roof area.
Next I repeat the process with white, heavily worked in at the top and roof only and gradually shaded in to about half way own the walls.
What you end up with is brown into sand, into bone into white.
Next I paint all exposed wood in Raw Umber and drybrush with bleached bone to give that sunbleached look.
The base is textured with sand and highlighted with bone and white to blend in.
Its an interesting question regards the size of the base. Some people make the building to fit the base and others make the base later to fit the size of the building. (You may think that sounds silly but I remember reading an article about Herb Gundt an incredible terrain builder in the States and he always said he made his models/bases to fit whatever box he had on hand to store them in at the time.)
Some do not base buildings at all. I like to just to protect the model from getting broken. Its suprisingly tough once rendered, but fragile balsa wood balconies, window sills etc can get chipped off.
I don' think it matters what you do, I leave a slight overhang with just enough area to stand a based figure on. Just remember if you have any parts of the model that are more fragile (Like the balcony on my recent model) make the baseboard bigger as this will help prevent the model getting knocked or broken in transit or storage. You don't want overhanging bits that get broken off because the model slides around in a box and is not proteced by a wider base.
The flagstones are all individuallycut to fit from plain thin plastic card.
I used a sheet of Wills plastic flooring for larger areas and then copied the pattern for the small areas around doors with individual tiles..
I started with thin card cut to about 1cm square, then took each one and cut it to different shapes as I glued them onto the model, trying to roughly replicate the pattern on the existing plastic sheet.So its totally random and looks time consuming, but actually was quite fun to do and took about an hour at most.
I wouldn't model opening doors unless you want to, its only my personal preference as I dont model the interior.
As to your comment about the Spackle. You can't go far wrong by slapping it on with a palette knife and deciding how rough you want the render to be. Thinned with water then sanded down once dry gives a smooth texture. For a rough look go with the Spackle straight from the tub. Neither is right or wrong, its up to you how you want it to look.
I am no expert on this and there are others out there who make stuff that surpases my talents. I have just applied techniques I have experimented with and adapted them to suit my style.
If you haven't got them already the Gary Chalk plans for building Adobe buildings as featured in Wargames Illustrated are excellent and show the step by step process. Somebone on this forum kindly emailed them to me yesterday as I wanted to see how they compared to mine. I can forward them onto you if you like.
I hope that helps, PM me if you need any other help. Looking forward to seeing the fruits of your labour.