Let me walk through the actual visa situation for Southeast Asia because the requirements differ by nationality and the misinformation is everywhere.

Thailand: 30-day visa exemption for most Western passports on arrival. Can be extended once for 30 days at an immigration office for 1,900 THB ($53). The Thailand Tourist Visa (TR) gives 60 days if you apply at a consulate in advance. The 'visa run' to a neighboring country for another exemption stamp still works but is getting scrutinized.

Vietnam: e-visa for 90 days is available online for most nationalities. Cost: $25 USD, processing 3 business days. This replaced the old visa-on-arrival letter system. Multiple entries. Worth noting: the e-visa covers most ports of entry but verify your specific entry point.

Cambodia: visa on arrival at Phnom Penh and Siem Reap airports, $30 USD. Also available online via the official e-visa portal for $36. The extra $6 online is worth it to avoid the queues and the pressure for unofficial 'fees' at the land border crossings.

Laos: e-visa available for $35, 30 days. Visa on arrival also available. No significant issues at either.

Malaysia: 90-day visa exemption for most Western passports, no action needed.

Indonesia: 30-day visa on arrival extendable to 60 days. The social/cultural visa for longer stays is more complex.