@Matt ********

Twice per calendar year is the general rule but as many say on here it's at the discretion of the Immigration officer if you attempt a 3rd time within a year and in most cases you will probably get in ok..

If you are concerned then get a cheap flight to Cambodia or another neighboring country and stay there for a few days and then fly back in and get another 60 days..

Flying in and out seems safer than doing a day run over a border and back again..

The bottom line is this...

If the immigration officer dealing with you on the day you enter Thailand from anywhere (land, air or sea) thinks you are abusing the tourist visa exemption system and living in Thailand and not a genuine tourist then you can be refused entry after more than 2 entries in a year.

But in reality this is unlikely but it's always a risk..

Doesn't matter what the agent says..

The only thing that does matter is what the immigration officer says when you dealing with him at the border.

Every country has different currency exchange rates ..

Depends on what you exchange into Thailand Baht

@Stuart **********

When you say.. "withdraw cash inside the bank"

Are you referring to getting a cash advance on a Visa or Mastercard account over the counter at a bank branch?

If that's correct what bank do you usually use for that?

You may need to try to get an appointment at the embassy and get a face to face meeting and explanation of the problem and an opportunity to correct whatever it is they think the problem is.

@Richard *****

A short cheap flight to either Cambodia or Malaysia could be worth looking at..

But check which of those countries are easier for entry on your passport..

Cambodia will likely require a visa (available on arrival) but not sure on Malaysia..

Book the flight in advance as it's likely to be cheaper

@Richard *****

The simple answer is yes..

Personally I would fly out somewhere for at least overnight and come back as it's just easier than long road trips to and from the border

No

@Mike ****

Depends on your passport country as to entry rules to Vietnam...

British citizen don't need visa before travel but US and Australia and other countries do..

Some airlines won't allow you to board the flight if you have a certain passport and have not obtained a visa before traveling

I would look at a flight to Cambodia and stay a night or two in Phnom Penh..

It's an interesting city with plenty of nightlife.