Hello,
I'm afraid I can only answer the bit about how it progresses as a relative of mine has had parkinsons for about 7 years.
I'm no expert, but progression seems to vary greatly between people. With my relative it started off with a shaking hand and has progressed reasonably slowly. She now also has stiffness when walking, shaking legs, and increased tiredness (possibly from tablets). Her physical symptoms are controlled quite well by her tablets. It seems as if the important thing is to get the balance of tablets right, and this can take some time but they make a big difference.
Although life is undoubtedly harder than it was before, and she has good days and bad days, she still manages to lead a reasonably independent life including cooking for her family, seeing friends and going for short walks.
Like I say, the progression will be different for each person, but you could try asking your neurologist how s/he thinks your progression will be. They may be able to give you some idea based on your age and the type of symptoms you're showing.
I hope you find some answers to your other questions. You could try phoning the PD helpline on 0800 8000303 if you have any pressing questions; it's staffed by nurses and they are very helpful. Good luck.