Cat Tree Advice And Litter Box Location

[brit1]

Recently brought my barn cat in and currently keeping her in my office for couple weeks and then will let her have run of house. Someone gave me a cat tree which she loves but I would like to get another for the kitchen area, looked onlinebut hard to determine which one is actually good quality - any advice on where to get a nice one (not too expensive). Also, will just having the one litter box in the office be sufficient for when I let her have run of house (just one floor level). TIA

 

[Chibisaurus]

Chewy Normally has great quality items, for a decent price.
This one (Below) is only $40

 

[GoldyCat]

One litter box may be enough, depending on the cat. Conventional wisdom says you should have 2 litter boxes, but not everyone finds that necessary.