Absolutely! I hope you have an excellent trip to the three vibrant cities of Hradec Králové, Olomouc, and Ostrava in the Czech Republic. Here are some essential travel tips for you:

Best Time to Visit:
The best time to visit these Czech cities is from April to October when the weather is generally mild and pleasant, although peak tourist season is from June to August.

Route and Accessibility:
Hradec Králové, Olomouc, and Ostrava are well-connected to major cities in the Czech Republic and nearby countries via train networks. The easiest way would be to start in Prague, from where you can take a train to Hradec Králové (approx. 2 hours), then to Olomouc (1.5 hours), and finally to Ostrava (1 hour).

Altitude and Acclimatization:
As these cities are at relatively low altitudes, you shouldn't have any issues with acclimatization. However, always stay hydrated and rested.

Accommodation and Booking:
There is a broad range of accommodation options from budget hostels to luxury hotels in these cities. It's always better to book your accommodation in advance, particularly if you're traveling during the peak season.

Clothing and Essentials:
Comfortable walking shoes are a must as these cities are best explored on foot. Dress in layers and pack an umbrella or raincoat just in case, even in summer as showers can be unpredictable.

Health and Safety:
Generally, the Czech Republic is safe to visit, but as with any travel, ensure your health insurance is up to date. Avoid deserted areas at night and always keep an eye on your belongings.

Local Etiquette and Respect:
Czech people appreciate it if you greet them in their language - a simple "Dobrý den" (Good day) goes a long way. Be respectful of the local customs, and refrain from loud and disrespectful behavior, particularly in religious and historical sites.