The requirements for the LTR are vastly more stringent. In the sense that you need much more money in the bank to qualify (and/or a quite high salary, although I understand they did away with the minimum salary requirement recently...you'd need to check on that). However, you'll probably still need to invest a minimum of US$250,000-500,000 in Thai bonds or real estate or something.
Same day returns by air are not the best thing to do. Stay at least a night. Anyone can find the time to make themselves more available. They might be busy this week but available next week. You literally only go out for a night or two. Easily doable over a weekend.
As a DTV holder, you're technically a tourist and can't use a flimsy excuse like "I'm busy working!" You can work from anywhere. You bring your laptop with you and work from Malaysia or Laos for the short time you're there.
You'll have to re organize your schedule I'm afraid. A weekend in Vientiane really isn't something one doesn't have time for. You can always fly there if time is short. Spend a night or two then fly back.
Firstly why not just spend a couple of nights in Vientiane? It's a fantastic place and you'll find food and experiences you will either struggle to find in Thailand or simply can't be found here.
Secondly, if you did have to do a quick turnaround, then just cross the border and come straight back.
Vientiane is 20km from the border crossing (technically, it's on the border but you can't cross there, you have to travel to the friendship bridge).
This takes half an hour or perhaps 40 minutes during morning or afternoon rush hour.
There's no point in spending the night near the bridge on the Lao side. Aside from probably not having any lodging available (I don't remember seeing any) whatever might be available is for locals and unless you speak Lao or Thai and can read the language, you'll struggle to make yourself understood in such places.
99.99% of falang head into town, where hotel staff can usually speak decent English. There will also be transportation available, which won't be the case if you were to spend the night in some dingy dive 3km from the border (if it's even available as mentioned).