after lodging your application it may take 3 days before you can collect your passport from the embassy so don't book any airline tickets until you have you passport. Today's prices for next week from Udon thai to Bangkok DMK is only about 1500b and to BKK about 1800b. You can get the international bus from the bus station in Vientiane to Udon Thani. The bus stops at both of the borders for passengers.
Once you have your visa you shouldn't have any problems with immigration. Go to Udon Thani and fly back to Bangkok as it will workout cheaper than flying from Vientiane. Land crossing back into Thailand makes your flight to Bangkok either airport alot cheaper.\
Mike The rent had been paid in advance when we moved in and the arrangement was in place from day 1. Both parties have to accept it or it doesn't work. The homeowner we had a problem with was a foreigner who liked to screw his tenants. A week before we moved out we requested he did an inspection and rectified any of his concern and had it in writing so we got the full security back. Im talking about country areas not Bangkok.
Recently my local immigration office came to check I was really living at my address. My Thai wife and I asked them why and the officers said too many fake applications so they have to check people are really live at the nominated address and also married.
When renting my Thai wife advises the land lord we wont pay the last month or two rent to get the deposit back. If the landlord had taken security for utilities we dont pay the lastmonthe power,water and intetnet
I had minor water damage with my passport with more than 5 years left until expiry. Went online and got a form to replace damaged passport. The cost is reduced as the replacement still expires the same date ad the damaged passport. Wrnt to the post office and lodged the form as per a normal renewal. If you are a hurry go to the passport office directly. Good luck