Reddit reviews A Field Guide to American Houses

Warning: Novel incoming.

One option for finding floor plans is the archive of Sears catalog houses here.

However, I'm going to take a different approach with the rest of my response, because it sounds like you have a lot of the same issues with gallery houses that I do.

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The easiest way to get around this is to understand the design process so that you don't need to copy other's plans. I suggest two of my text books from design school:

• The Interior Plan by Robert J. Rengel. Amazon. A used 2011 version can be had for less than $20.
  
  It's a professional book, but it's meant for 1st and 2nd year students so it's not overly technical. I like it because the drawing style is loose and approachable, and it's a very comprehensive. It will walk you through the creative process and will give you planning tools you can use to come up with your own floor plans later on. There are sections on both commercial and residential design, separate sections on individual rooms, and then how those rooms fit together into a whole building. It even talks about furniture placement!
  
  
• A Field Guide to American Houses by Virginia & Lee McAlester Amazon. Again, get the old version used. Less than $10.
  
  This one focuses on exteriors and has both photographs of homes in styles throughout history and line drawings showing what elements make those homes an example of that style. Because it separates out the elements, it's easier to adapt them to new buildings.
  
  If you really want to get into it, I think it's worth it to get the books. They'll have a depth of information you just can't get online - especially in terms of picking up the design process and explaining why things work.
  
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  In terms of adapting real-world measurements into the Sims...I don't advocate for it. Every time I try, the proportions are messed up visually and/or the room sizes don't translate well for sims furniture and activities. I find that it's much, much better to base room sizes on the furniture layout you want and how much open space you need around those arrangements. In other words - work from the inside out.
  
  Say you see a floor plan with furniture on it - a couch, chair and coffee table. It doesn't matter how big those pieces are in real life and it doesn't matter how big the room is, either. Why? Because you know how big that furniture is in the sims and that's all that matters. You need a room that will accomodate a 3x1 tile couch, a 1x1 tile chair, and a 2x1 tile coffee table, plus walking space. You can do a similar thing by translating building facades into 1 or 2-tile windows and doors. I usually work from what minimums I know work in the game and then add space depending on how luxurious I want it to be. Just keeping in mind how much space each item takes up in the game is immensely helpful.
  
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  I like to harp the most central part of really good design: build for your clients' reality.
  
  Don't build a house for humans. Build a house for Sims. Maybe it's just me, but it annoys the crap out of me when I see fake garages and storage rooms in TS4 houses. It's a waste of potentially useful space and family funds. Also, Embrace the weirdness and don't forget about cool things like bubble blower lounges and rocket ships! If your sim has a weird hobby, don't forget to dedicate space for it.
  
  One last thing! Minimize your corridor space! It's dead space so please, please don't make long rambling hallways. Looking at good plans will help you avoid that. Our professors nagged us on this all the time.
  
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  Ninja Edit: I thought it might be helpful to list out my process steps, so here it goes.
  
  

1. Make a written list of spaces and equipment needed based on the family who will be living in the house. Be sure to include hobbies and activities. This is meant to force you to think about details. For example, how many kitchen applicances you want will change the size of your kitchen - so decide early!
   
   
2. Draw a bubble diagram (loose circles) to figure out room placement and room relationships. How do you want the house to flow?
   
   
3. Start adding shape to the rooms. Include doorways, windows, furniture.
   
   
4. Use sims furniture size and walking space requirements to determine total tile dimensions for each room. Then add together for the whole building. Note: I draw plans inside out. Then build it in the game outside in.
   
   
5. Choose a lot size based on the house size and desired yard size. So this is where I start building in the game.
   
   
6. Refine room dimensions based on exterior details you want. Make sure that the windows and doors will space properly on the facade. Make small changes based on furniture sizes, activities, etc.
   
   I know it's a lot of front-end work, but it saves so many issues down the road. You never have to run out of room, or have too much of it, or have to go back and re-do stuff if you plan a little.

https://www.amazon.com/Field-Guide-American-Houses/dp/0394739698

A Field Guide to American Houses by Virginia and Lee McAlester.

It's designed for exactly this kind of question :)