Some things are easier to fix than others...
For the Hamada's home that has an arch in front of the door and the back door set as the front, I delete the arch and the walls underneath as well as the gate. I add gate on the sides of the path leading to the front stairs. I also extend the sides of the yard by adding a diagonal wall on each side and moving the fence out one tile. (*The front door needs to set as the front door too.)
https://iamciane.files.wordpress.com/2015/02/screenshot-60.jpg
Babes on Beach. Again, I used CFE to level the terrain, but you might extend the deck instead. (If you extend the deck, move the porch steps a tile away from the house for paper delivery.)
Cntl/Shift/C: testingcheatsenabled true, constrainfloorelevation false, level ground around stairs foundation so Sims can stand there and talk to each other. Level the tiles on the foundation porch if they get messed up when the ground was leveled. The reverse your cheat codes order and type: Cntl/Shift/C: constrainfloorelevation true, testingcheatsenabled false.
Use terrain lowering and softening tools to make a more gentle path to the mail box and level area at base of path by mail box for Sims to congregate.
You decide how much or how little you want to do and see how much better your game plays.
Once you have fixed everything, "save as" IPfix BEFORE you start playing. Copy it outside your Sims 3 folder as a backup. Then use "save as" to immediately rename your game for playing. (You can do this for all your worlds, setting them up the way you like once and playing in copies of your worlds.)