What size floor space would be required to build a single story
restaurant and kitchens. It would need to seat up to 300 people. Part
would be for families and part for more private dinning.

Hello dododiddy,

Here are some guidelines that may help

1. see "Section: Furniture / Tips: Seating Guidelines" at
http://www.kitcheneering.com/furniture.html

"In preliminary space planning, the "rule of thumb" for deciding the
area requirements for a restaurant is:
Dining Room: 60 percent of total area
Kitchen, Cooking, Storage, and Preparation: 40 percent of total area"

"When originating space requirements, remember that "banquet" seating
may use as little as 10 square feet per person, while fine dining may
require 20 square feet per person. A good average for restaurant or
coffee shops with general menus is about 12 square feet per person.
This will allow for traffic aisles, wait stations, etc. "
...
It then goes on to give recommended square feet per person for
different restaurant types. And, Square footage for wait stations,
etc.

2. This site has diagrams of seating arrangements
see "Chair and Table Spacing Requirements" at
http://thechairfactory.com/catalog/space_requir.php

3. In "Questions to ask an Architect" at
http://www.hospitalitynewsgroup.com/articles/2002/200209_architect.shtml

"Q. How do I determine how big of a restaurant to build? Let?s say I
want to seat 125 people.
A. A rule of thumb is that you should allow 32-square feet per person
for a sit-down restaurant, and 28-30 square feet for a quick-service
operation. That number includes everything from the seating area to
restrooms and kitchen. So a sit-down restaurant to seat 125 people
should be 4,000 square feet."


You may find more information in the other search results

Search string:
"square feet per person" restaurant