How do we navigate visa options and requirements as Australian and Dutch passport holders traveling to Thailand for two months?

When you arrive you will be stamped in without a visa.

It is called VISA EXEMPT for 30 days extendable once for 30days, 1900baht

If you obtain a TOURIST VISA before you come by embassy or online e-visa, it will give you 60 days and extendable 1 time 30days, 1900baht.

If you were to leave the country and come back, you can do the same VISA EXEMPT 30 days plus 30 days one time.

These are your basic tourist options.

Google : onward ticket. This caters for the matter that you might be asked for a ticket out of Thailand, either by the airline or immigration. The first more likely, asked at check in.

There are ATM's after immigration before baggage reclaim.

So much bad information in this post.

You cannot be issued any visa upon arrival. You qualify for VISA EXEMPT which means you have NO VISA, and you will get stamped into Thailand for 30 days upon arrival. You cannot apply for a tourist visa inside of Thailand. Period. End of story. Not possible.

If you want a tourist visa you have to get that BEFORE you come to Thailand.

Visa exempt can be extended ONE time for 30 days, giving you 60 days total in Thailand. This extension must be applied for in person at the local immigration office.

Why would Thailand have an embassy inside its own country? Embassies and consulates are in foreign countries. There is no Thai embassy or consulate inside Thailand.

It's very likely your airline will not let you board a flight to Thailand if you cannot show them proof of travel out of Thailand within 30 days of your arrival. This is because you have no visa and you are only guaranteed 30 days, so you must be able to show you will be leaving within those 30 days. So if you are planning on going to Cambodia, buy your bus ticket and show this to the airline when you are checking in. You can't just take a rented vehicle across an international border, so your plan to ride a motorbike to Cambodia is not possible.

When you return from Cambodia you will be stamped in for another 30 days visa exempt, which can once again be extended for 30 days. You can only enter via land border 2 times per year using visa exempt.

There are generally no ATMs until after immigration. If asked to show proof of funds, you will need to show 20,000 baht, or the same amount converted in a major foreign currency (dollars, euros, etc). This must be in cash and cannot be a banking app, bank statement, credit/debit card.