Houseboat dwellers will have problems accessing their homes by boat at some ports: Port Primavera, Premium Port, Port Pleasant and PortPlaya. The ports themselves can be accessed without any problems; it's only when trying to visit houseboats there that route failures and freezes occur. The failure only occurs when a Sim tries to route to a houseboat from a certain angle. For example, a Sim has no problem getting to their houseboat if they approach it by boat from the right, but will get horribly stuck when they approach it from the left.

Some suggested solutions:

Delete Rubisel houseboat or put rocks at the waterline to avoid townies getting stuck.

Empty houseboats, putting everyone in other houses.

Put some rocks where all the NPCs get stuck near the Premium port.

On the ports with rocks too close to the port exit stairs, move or delete them.

Romantic houseboat - remove the trees between the two houseboats that are blocking the road in town/world edit mode.

Place plants/rocks between Premium and Pretty Port on water/ground edge.

Place a NoVisitorsAllowed boat on Port Pleasant.

Evict everyone who lives in a houseboat. Delete ALL houseboats and their lots. Move evicted families to new homes.

The cheats for editing ports and dive spots are:
testingcheatsenabled true
enablelotlocking on
buydebug on

When you enter the cheats, you click on the port you want to change. (In the right part of the window opened, there will be a padlock icon. If you click it, the lock will open and you can then enter buy/build mode.) Remember to turn off all the cheats in reverse order, changing on to off and true to false.

Other helpful fixes:

Use discoverAllunchartedislandscheat to delete most of the laggy fog
Get Ellacharmed fixed version of Isla Paradiso: http://www.modthesims.info/download.php?t=514909
Install *twallans NRAAS overwatch* mod! (Highly recommended! You do nothing after installing it. It does everything on its own.)

Also get twallansNRAAS register mod to annihilate the Scott family and remove horses and wildanimals.

Delete all boats, place the residents in other houses, and delete every boat-platform. (Extreme, but...)

Turn off Pets.

You probably will have lag at 8 a.m. when carpools and school buses head out and it gets worse the more children are in town. (You can add new schools for any new kids, but moving ones currently enrolled will cause grades toreset.)

Once you have fixed everything, save as IPfix before you start playing. Copy it outside your Sims 3folder 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.) 

1. Homes with arches as entrances look pretty, but keep everybody but family from the door.
Collins - Colonial Casa - 76 Civic Center (Also, the front door is set incorrectly and stacked spiral stairs cause problems accessing top floor, so replace with a ladder or delete access to top floor.)
Ichtaca - Castillo de Ichtaca - 1 Camino del Ray (Also, delete stacked spiral stairs. Replace with ladders or simply delete everything in top floors and make rec room into a bedroom. Set front door to the actual front door.)
The Lone Artist - Adobe Abode - 11 Ocean View Road
(Empty home) - Personal Paradise - 9 Sea Spray Lane

2. Weird, wrongly set (or unset) frontdoors:
Alto - Luxury Villa - 1 Alto Road (Also, the platform that surrounds the right side is needs CASting.)
The Siren - The Modern Hideaway - Dry Land, Kraken Island (Set front door as the one in front. They want to enter the side door behind a wall!)

(Empty) - Modern Marvel - 10 Modern Mile (There is no front door set and very unlevel terrain. Level some.)
(Empty) - Bachelor Pad - 69 Paradise Road (No front door is set, but it has only one door anyway)
(Empty) - Seaside Escape - Sandy Shore, Surf Island (No front door is set, but it has only one door)

3. Other problems:
Babes on the Beach - Holiday House - 25 Riviera Road (There is NOT enough flat space around the entrance. Sims often get stuck in the tiny flat space behind the entrance foundation. Flatten the ground around the foundations and smooth the incline to the mailbox.)
Hamada - The Spanish Queen - 7 Sea Spray Lane (Front door is all fenced in, so the only entry is through a structure with two arches.)
Vidal - The Painted Lady - 74 Civic Center (The whole yard is fenced in and entrance is too small.)

Check toilet locations that block the showers/baths. (Houseboat for Rubisel Ichtaca is one.)

Check for stacked spiralstairs (which can cause route failure). Use ladders or delete topfloors.

Medina house (Add fence around stairs. Then remove garage door and spiral stairs to top floor.)
Amigos house (Fix the access to top of the stairs.)

Remove Spirit of the Sea house or just seriously de-clutter it. (There is not enough room to move around.)

Spanish Resort - Delete the fencing around the trees in the middle of the pool.
Hobart's Resort - Change to no-visitors allowed. (Only your playable Sims canvisit so no stuck Sims.)

Fences in the artcentre - delete the corners.

The Scott family are corrupt, but do NOT delete them unless you have a trusted mod set up to do that safely. Simply move them to a new home to reset them.

I do things the hard way. You don't have to! I've made a spreadsheet. It links directly to the store. It shows what sets are included in all the compilations and if they repeat.

Just download the excel spreadsheet if you have Office with Excel OR download the other one, if you don't.

All sets are hyperlinked to go directly to the page you need in the store to get that item.

Click on the BLUE hyperlinks to download those worlds, venues, compilations, and sets. If it's red, look for the repeats. You'll only want to install a set once. If the hyperlink is purple, that is the part of the compilation I installed to avoid repeats.

All black underlined items are hyperlinks and can be installed if you don't have all the compilations. Just watch out for red duplicates!

If you have questions, ask! Spreadsheets include links to everything we could find a link for in the store. :D

Excel Spreadsheet with links:
http://www.4shared.com/file/Hec8hy2Yce/THEstoreList.html

Open Documents Spreadsheet with links:
http://www.4shared.com/file/4N6jn2zuba/THEstoreList.html