The hotel is sort of businessmen use type hotel and inside restaurant offers not so expensive prices in general but I recommend to try convenience store’s Bento box if you want to save your money.

There are many street restaurants Japanese style fast foods(Beef bowl etc.) and convenience stores between the hotel and JR Tamachi station within 10 minutes walk. Don’t miss 100Yen shop Shibaura, near Berger King before reaching the station.

JR Tamachi has two side exits, one to tokyo bay side(Koonan exit and one to opposite side(Mita exit) and you can cross over on the train rails to Mita exit from Koonan exit freely.

Fromn Mita exit, you can pick up taxi to Tokyo tower easily. It costs about US$10 and takes just few minutes. After Tokyo tower, you may drop in Zojyoo-Ji temple and take subway from Onarimon to back away to Mita(next to JR Tamachi).

Talking about AEON Shinagawa seaside shopping mall, it depends what kind of interest you have. I like to take a walk in such family shopping place. It is neat and pleasant and very thrifty. It opens around 10AM to 11PM usually.

It may cost about US$15 one way to there by taxi from the hotel though. The food court prices must be lower than the hotel dining absolutely. You can try to take a monorail from Shibaura-futo to Daiba in Odaiba where is one of modern town where is a good view of Tokyo Bay if it is fine day and Aquacity mall and some more fun places there.

It takes just 30minutes from the hotel to Daiba.

Hop on the JR Yamanote Line that makes a loop around the city and you’ll be at all of the cool locations in minutes: Shibuya, Shinjuku, Harajuku…

Don’t bother with taxis unless you miss the last train home – they’re expensive and the drivers often wind up driving all over town when they have a passenger who can’t explain where to go in Japanese. (Carry a business card from your hotel to hand to the driver if you’re heading home, as it will make it much easier.)

If you’re looking for good cheap food near your hotel, keep an eye out for Denny’s or Jonathan’s family restaurants. When you’re traveling, it’s great to be able to pop in and eat something easy like a sandwich or bowl of spaghetti. Of course, you’ll want to do a lot of sampling local fare like conveyor belt sushi, ramen, tempura, all of which can be had cheaply, but the family restaurants are great because they are open 24 hours, so you’ll have somewhere to go when you have jet lag.
There’s a Caffe Veloce right outside your hotel, they’re not bad for a quick coffee and snack.

As for walks, you’re right near the water so you can explore. You’re also not too far from Tokyo Tower, which is a good place to walk to, since you will be able to see it from many points along the way. There’s a nice park surrounding it and Roppongi is not far from there.

Have a fantastic trip!