When Shri Vallabharyaji first founded the sect, he wanted to establish a new type of "house of God", one where God and devottes would feel at ease. The first temple for ShriNathji, was designed as a traditional Hindu temple, with a spire, on top of the mount Govardhan. Since than, the havelis have been designed more or less as a mansion / palace.
Since the early days, havelis have been designed to have numerous rooms, interconnected by courtyards, often arranged in non-liner array. The rooms and courtyards have a beautiful symetry, and yet, the arrangement of courtyards leads you in anything but a straight line from the main gate to the inner sanctum.
Traditionally, palaces and mansions kept visitors from guessing
where the centre of the building lay, or how to get to it. This served two main
1) to keep strangers out / away from the inner core of the palace
2) keep the place safe from looters.
When the sect was developing, maurding muslim armies were only too willing to loot Hindu places of worship. For this reason, the buildings of the rich were built like mini-fortresses, with strong, reinforced doors, a confusing layout of rooms and series of courtyards to keep stangers from guessing where anything maybe !
The Haveli's various functional rooms were called
"ghar", further reinforcing their "family" / house like feel.
Hence, we have
Paan-ghar - where beetle-nut leaves are prepared for the Lord.
Ful-ghar - where garlands are made.
Darji-ghar, where clothes and soft furnishings for the haveli are stitched.
Jal-ghar, from where water is drawn (usually from a deep well) / Yamunaji and brought for seva.
Saag-ghar, where vegetables are prepared for the bhog of the Lord.
Rasoi-ghar, where bhog /prasad is cooked for the Lord.
One of the main themes in a Pushti Marg's haveli is that the nij-mandir (inner sanctum) is never placed in a straight line from the main gate to the haveli. This is to avoid stangers from peaking into have a look at Ladelelal or inadvertantly casting an evil eye on the darling child of Yashoda.