Thank you for your interest in Experimental - as the name suggests, it is still under development, but I will answer your questions as best as I can.
1. With Pak128.Britain-Ex, the game should in principle be playable from 1750 to the present day, but the pakset has not been balanced yet. Proper balancing will require a number of new features which will be difficult to implement, so it might be some time before this is done, but it is planned.
2. There are some threads in the forum about compiling (the procedure is very similar to that for Standard), but you may find it easier to download the executables compiled by a third party here
3. The timings, acceleration, etc., are balanced to be as realistic as possible (and, unlike the financial balancing, this has largely been completed). You can see the distance in kilometres between each stop in the schedule dialogue. You can therefore work out what would have been a realistic amount of time for that sort of vehicle to have taken to complete that sort of trip in reality. You might also find the convoys' average speed graphs helpful in estimating this. Note that passenger happiness is not something modelled directly, although journey time is.
4. The station coverage works very differently in Experimental to Standard. In Experimental, passengers can walk all the way to their destination, can walk some distance between different stops as part of their journey and will take this walking time as well as the walking time between the origin building and the origin stop and the destination building and the destination stop into account in determining the optimum route. The coverage area represents the maximum distance that passengers can walk to get to the origin stop and from the destination stop, but, because passengers will only travel if the overall journey time is lower than their journey time tolerance (which is randomised for each passenger trip) and because passengers will always take the quickest available route from their ultimate origin to their ultimate destination, the less walking that passengers have to do to get where they want to go, the more likely it is that passengers will use your services. Thus, in Simutrans-Experimental, it can often make sense to have multiple stops with overalpping coverage areas. Just as in real life, one might walk a mile to the nearest railway station or alternatively take the 'bus from a 'bus stop a few hundred meters from one's house.
5. Can you elaborate on what you mean when you re fer to ships not working; in what way do they not work?