Hello! That sounds like an exciting trip to Uruguay. Here are some travel tips for your visit to Montevideo, San Gregorio De Polanco, and Colonia Del Sacramento.

Best Time to Visit:
The best time to visit Uruguay, including Montevideo, San Gregorio De Polanco, and Colonia Del Sacramento, is during their summer from October to March. The weather is pleasant for sightseeing, and you can enjoy beautiful beach walks. Avoid the peak summer season (December to February) if you prefer fewer tourists.

Route and Accessibility:
You can start with Montevideo, fly into Carrasco International Airport, which has good regional and international connections. From Montevideo, you can hire a car and drive to San Gregorio De Polanco (around 5 hours). Finally, drive down to Colonia Del Sacramento (about 4-5 hours). Regular bus services are also provided between these cities.

Accommodation and Booking:
These cities have a range of accommodations from budget hotels to luxury ones. It's best to make bookings in advance, especially during the summer months. Online platforms like Booking.com or Airbnb work very well in Uruguay.

Clothing and Essentials:
Pack lightweight, breathable clothing for the warm weather and a good pair of comfortable shoes for walking. Don't forget to pack your swimsuits for beach activities. Sunscreen, sunglasses, a hat, and a reusable water bottle are also must-haves.

Health and Safety:
Uruguay is generally safe for tourists. However, basic precautions should be taken like not leaving belongings unattended and avoiding deserted areas at night. Regular vaccinations as recommended by WHO should be up-to-date. Tap water is generally safe to drink.

Local Etiquette and Respect:
Uruguayans are friendly and welcoming. It's respectful to greet people with a kiss on the cheek. When visiting rural areas or small towns, dress modestly as a sign of respect.