I was actually more concerned about the Myanmar government doing this. Even only a small incident usually results in foreigners being banned for years.
There are sometimes exceptions along strategically important roads - like occurred in 2014 when there were some attacks in Kawkareik, along the then newly opened Myawaddy to Hpa-an highway. Foreigners were not banned from travelling that way because the government felt that incident was a one-off. Later, in mid 2015 some attacks occurred on both the old and new bypass road, at that time not yet officially opened. Foreigners were prevented from travelling that way only for about 10 days until the situation was brought under control. I was personally impacted by this.

You are also correct about foreign governments doing this, but it's the Myanmar government's rules that will determine whether a foreigner can go to a particular area or not.

In Thailand's case, Australia considers the whole country to be "exercise a high degree of caution" even though most of the country, especially rural areas, the northern and north-eastern parts are as safe as anywhere else in the region, including Laos, Cambodia and Vietnam. Yet those countries have a "exercise normal safety precautions" except for the Saisomboon region of Laos, which varies between "reconsider your need for travel" and "do not travel". At the moment, it's the former.

Myanmar is also "exercise a high degree of caution" overall, but strangely enough not for Yangon, Mandalay, Inle Lake etc. Yangon has had bombings and political violence and while I find it safe, I think it's a stretch to consider Yangon safer than say Bangkok or Chiang Mai. It's about the same. Also, if one takes the Australian government's warning to the letter, they advise against all travel to Myanmar's border regions thus meaning they advise that you don't enter or exit overland. Only fly in.

Therefore, sometimes the advice of foreign governments is a bit over the top. I don't think foreign government travel advice alone will affect tourism much; besides, Australia's advice to be cautious in Thailand hasn't slowed down visitor numbers to that country, which are 37 million a year, including 1 million Aussies and counting. What has slowed things down is a bad exchange rate, poor value for money, tourist safety, scams etc.

Renewed fighting will be what puts the nail in the tourism coffer in places like Hsipaw and Pyin Oo Lwin. Let's hope it doesn't escalate any further.

I'd suggest you fly to Chiang Mai from Singapore then.Spend a few days there.

Then fly down to Phuket or Krabi and visit one of the west coast (Andaman Sea) islands.Its a good time of year for those.Have a look on Travelfish for differences beteen the various islands.

As numerous people have already said- if you want Western standards, you need to go to Thailand. That is why none of us leave home without travel insurance.

Thanks for your recommendations everyone. Rather than running around SEA we've decided we're going to stay in Thailand. I thought about it, and bthdth is so right about the convergence of ambiance for the better known places in the region...

Now some specific questions:

In the north, would you recommend heading to Chiang Rai or Mae Hong Son from Chiang Mai? Which has more day trip options outside of trekking? Which has better scenery en route?

And despite her aversion to swimming, mom would like some beach time at the end of our trip before she heads back to the Canadian winter. For logistical reasons, we're probably going to end up in Phuket or Krabi (I need to catch an international flight out before my visa expires). This may be asking too much, but are there any quieter beaches with low-rise development / a nice walkable town with local dining options (not too Westernized)?

Our budget is also 1 to 2 stars. Thanks!

How long would be enough time to stay in bangkok upon arrival before going to siem reap? because once i get back from LP, laos, ill be going to Chiang Mai then back to bangkok and go to ko tao and krabi.. i have 3 months to work with so i think i have enough time since my itinerary onlys gets me staying in cambodia for about 5-6days and then vietnam for 15-20days, laos for 5-6days?

You shouldn't have any issues with local unrest in Thailand or Laos. Some of the more remote villages in Laos can be a little wild - I've never had any problems whatsoever, but use common sense, particularly when deciding where to try and spend the night.

Chiang Rai province has some beautiful, interesting places. Mae Salong has an interesting history, and lots of options for hiking in the surrounding countryside. For more off-the-beaten-path places in Laos, head to Muang Sing and the surrounding region. I don't know if much has changed there recently: I haven't been since before they built the bridge to Burma.

Good advice, but there's no unrest on the Thai side anywhere except in the far south along the Malaysian border. There has been some sporadic unrest in Saisomboon and areas along/adjacent to routes 13N between Phou Khoun and Kasi and on the new road between Kasi and Muang Nan, but that seems to have died down in the past year or so. Even so, as you say, it's good to take precautions and definitely avoid night time travel.