There are loads of notes on Bangkok here. I like the Shangri-la or the Oriental which are pretty close to each other. Or the Grand Hyatt Erawan. Each is walking distance to Silam road which had the great all-night markets. Not quite a family atmosphere with all the nudie-bars, but the shopping is fun. During the day, a visit to the old palace/temple is a must. Bring water and expect to spend hours there in the heat absorbing the culture.

As for Tokyo, yes of course you should visit. If the weather is nice, I recommend taking the Narita Express to Yokohama where there are plenty of excellent hotels and a neat amusement park on the harbor. Of course in Tokyo there is plenty to do.