Setting up an Airport roaming network

1. Yes.. very reasonable except your use of Express as the main router.

See more on your point 3.

2. The new airport utility is much better and should detect the setup..

So the best way is plug each secondary router into the main router in the basement with just a patch cable.. and then run through the setup.. make sure it shows extend by ethernet.. will post more screenshots shortly.

I also strongly recommend.. use short names <16 characters, no spaces that are pure alphanumerics. Passwords the same rules but can be longer.. use different passwords for wireless and admin..

3. Express are much slower.. they use 100mbps ports so if your cable speed is >100Mbps then DO NOT USE EXPRESS. They are not up to the task. Even if your speed is say 80Mbps I still would not use the Express.. it is a toy router.

4. As long as primary router is set with guest wireless then secondary WAP can use it as well.. but test how well it works in your other areas of the house .. Apple have set it to be very slow.

Your other setup can work but is more complicated.. and in fact you would do better with a main router that is NOT Apple. So try the above first.

Ran out of edit time.. but as Bob notes.. the old method is now better ignored.. simply plug the two together and run through the setup wizard.

I made up a new set of screenshots..

1. Plug the new or reset router WAN port by short patch ethernet cable to the Main router.

It will appear as (1) in Other Wi-Fi Devices.. which you can just click on.

2. Click on the new device that needs configuration. (Note by doing this over ethernet it is often more reliable than using wifi. Both should work!!)

3. The setup wizard guesses your intention to extend.. the only confusing thing is it picks the original TC 5ghz wireless name.. for now just ignore this.

Give your new airport a short sensible name.. NOT APPLE RECOMMENDED.

When you have lots of airports just number them or short statement of location.

4. This is the most important screen in the sense it is deciding how to extend.. NOTE carefully.. Using Ethernet.

5. If everything works you will get Setup Complete.. click Done.

6. Check the Airport utility that both are now shown as working.

7. If you have many airports to configure.. once you finish the first.. take it to the location you wish to place it.. plug in and power on..

Then go back to do the next one.. again in the basement with a short patch lead.. direct.. it works much more reliably this way.. but if things go wrong don't worry.. the setup can be done manually in a snap.. more coming.

Is the above setup reasonable?

This will depend on whether your Internet connection is 100 Mbps or more, or if you plan to go to a faster connection in the future. Why? The Ethernet ports(s) on an AirPort Express are limited to only 100 Mbps, so that would be the maximum speed that could ever be attained on the network with the AirPort Express acting as the "main" AirPort.

The AirPort Extreme can easily handle a 300-350 Mbps Internet connection, so that would normally be the AirPort that would want to think of as your "main" AirPort if your speeds are higher than 100 Mbps, or you plan to move to a faster plan.

Um, how do I actually configure this? All of the instructions I've found either reference a "wizard" (e.g., Roaming Network with Extreme and Express) or show screenshots that look very different from my Airport Utility (e.g., Wi-Fi base stations: Setting up and configuring a roaming network (802.11 a/b/g/n) - Apple Support)...

Best to totally ignore that ancient Apple Support document, since it assumes that you are using an 8+ year old version of the Mac operating system. The document has virtually no relevance for users who are using a current or recent operating system (within the last 6-7 years) and will only serve to confuse if you try to use it as a reference.

We'll provide a few tips on using Apple's setup "wizard" once you decide to move forward.

Are the Expresses and Extremes basically interchangeable for these purposes (other than antenna size and number of LAN ports)? I.e., any reason I can't use an Express as the "master" like I've described above?

See the answer to your first question above. In addition, the AirPort Extreme provides far better WiFi antenna performance compared to an AirPort Express, so you would want to keep that in mind as far as the location for various AirPorts.

Ideally I'd like to use this setup to create both a main and a separate guest network. Is this possible to do?

Yes.....IF.....the device that you call your modem is a simple modem......not a modem/router or gateway device. By that, we mean that the modem does not provide any kind of router or WiFi functions. A simple modem will have only one Ethernet port. A modem/router or gateway will have 4-5 or more Ethernet ports.

If you are not sure what type of "modem" that you have, post back with the make and model number of your device and we'll do some checking.