If you bring in over $20,000 USD cash (or equivalent), then you have to declare it, no matter how you are entering. Most countries have a similar requirement, although the amounts may differ.

The 10,000 to 20,000 BAHT is a different scenario, for tourists and visa exempt. They want to see that you can support yourself. They don't want to see credit cards or statements, they want to see cash. And there are no ATMs in BKK between the gate and Immigration. So you have to bring it with you. I once had to count out $500 USD in $50 notes right there on the immigration counter.

There IS however on the books 10,000 to 20,000 baht that they can request proof of on tourist or exempt entry. They want to see cash in pocket, not credit cards, etc.

Not asked nearly as often these days, but can still be asked for.

There is more to do around DaNang. Not necessarily IN DaNang. They have nice beach front too.

DaNang has more of everything. So DaNang gets my vote.

How much time do you have? Do both. It could be me, but I think you have more fun in Penang if you know locals.

You are basically trying to live in Thailand, without being a "tourist" in Thailand. They are just suggesting you apply for a long stay visa.

Assuming your passport allows (American, British, Australia etc) A tourist visa is good for 2 months right off the bat. You can also arrive without a visa at all and get 60 days exempt currently (this will probably go back to 30 days exemption sometime this year, so keep an eye on that).

Whatever country that wants to let you in. DTV is Thailand specific.

Depends on when and for how long you are coming for. In one or 2 months (I am not sure of the date), you will need to fill out the arrivals card online before arriving. Sometime later this year or early next year, you will need to get an ETA.

Also, that 60 day visa exemption (it is not a 60 day visa) may be shrinking back to 30 days soon.

Again, all depends on when you are coming.

No. Once you have left Thailand, you get a fresh 60 days when you go back to Thailand.

You answered your own question.