i am in the process of getting a White Rotary Treadle Sewing Machine but have no idea about this machine. what i will be doing or need for it are:
1) new machine to me, so sounds great to work on.
It is.
2) is this a forgiving machine, easy fix, less maintenance, durable ? i have not been near a white rotary machine.
Yes, yes, yes, yes, go ahead and get next to it they don't bite.
3) will i be able to keep it and if i want to can i use the treadle and put in a singer sewing machine? will be it an easy
adaptation? meaning if i want to put a singer machine i don't need to cut/add woods in it ?
Why wouldn't you be able to keep it, is it gonna run away? No, a singer uses different hinge spacing and has different measurements at the base, and the cabinet would need major modification. That cabinet is too good to butcher that way.
4) is this a desirable machine that i can keep for myself ?
Yes, it's desirable, I want it, so you'll have to share it with me.
5) i need a durable (like i don't have any) single stitch machine with treadle. or a singer treadle will be a better one ?
Durable? Heck yes. I've got four or five white made machines and each one will out sew their contemporary Singers.
the seller is willing to let go of it for $35. appreciate any inputs as this will be the first white rotary i will be working/using.
In stead of asking these questions, you should have gone and got it then bragged about what a great machine you got for a steal. 
thanks a lot,
You're welcome.
vic
Joe