Can't agree more with the Dan and Protohyp.
It all depends on how much are you willing to work on it. $1300 sounds right if the trailer has a title, if it doesn't then is a little too much, specially here in FL where there is a lot of them W/O title.
How far do you need to tow it from the seller's place to yours?
Also We totally understand that there is a lot of work involved on it, but honestly: Unless you buy an already restored AS for about 10K to 15K you will need to work on it regardless.
Now the good news is that with a gutted trailer you have the chance to make it just how you want it, and specially if you guys are planning to full time.
It will all come to 3 things according to our experience:
1) Do you have the vision of what you want?
2) Do you have the time to invest on it?
3) Is your budget realistic according to your expectations.
You will find plenty of help here, from the right size of drill bits up to other members donating parts that you may need.
This forum is just a great place with amazing people willing to help 24/7, and you will see, post a good question ad 11pm and by 6am the next day you will have few replies.
If we can help on anything just let us know. We are currently working here:
to make our fulltime space.
Please keep us posted