Hi there Elli!
Good choices for a 7 day trip! Firstly, I've plotted your itinerary out for you so we can see what sort of trip we're dealing with by calculating the prices if you were to buy train tickets in Japan:
- Tokyo > Osaka: ¥13750, (194mins, 556km)
- Osaka > Kyoto: ¥540, (29mins, 42km)
- Kyoto > Nara: ¥690, (44mins, 41km)
- Nara > Osaka: ¥780, (55mins, 48km)
- Osaka > Tokyo: ¥13750, (194mins, 556km)
TOTAL: ¥29,510 for 5 legs
Note that I didn't include any travel around Tokyo, or from the airport into Tokyo (¥6000 return).
Based on this, here are some answers to your questions:
- How much hours with take from Tokyo to Osaka (fastest train)
The very fastest train will take 176 minutes, it is a Nozomi train and will cost ¥14,050. If you use a Japan Rail Pass, you have to take a Hikari, which is a slightly slower bullet train (18 mins more at 194 minutes).
- I can use the pass for different places inside Tokyo as well.
Yes, inside Tokyo you can use it for the JR Yamanote line, which is a circular line that loops through Tokyo. Personally I find it very handy, but you will also want to use the metro which is none JR and not covered by the JR pass. Here's a map showing the JR routes around Tokyo with the bullet train interchanges clearly marked. You can reckon on saving around ¥200 per journey if you use these JR lines with a rail pass.
- Which station in Tokyo have direct train going to Osaka (and to which station in Osaka)
Both Tokyo and Shinagawa have direct bullets going to Shin-Osaka, which is the bullet train terminal in Osaka. From there, you will need to change to a short local train to take you right to Osaka station (4mins).
- How much will cost with and without pass (in 7days)
The cost of a 7 day Japan Rail Pass is ¥28,300. Not taking into account your journey to and from the airport and possible use in Tokyo, your travel comes to ¥29,510 making it slightly cheaper to use the Rail Pass (and a whole lot more convenient). Given it sounds like you'll be travelling with luggage, I would recommend the rail pass simply for convenience at the stations.
- With pass, seat is reserved or there is extra charge
Yes, with the rail pass, seat reservations are free, and you can make them as soon as you activate your rail pass in Japan.
- If no seat reserved then what timings are less crowded
In general non-rush hour are less crowded. So try to avoid 7-9 and 5:30-6:30.
- Is there lockers in above cities station and there is any limitation for size/weight
Yes, there are lockers in all of these city stations, although I suspect Nara will have a more limited selection. For the nara visit you can always leave your belongings in Kyoto where there are many more options, including a left luggage service if all the coin lockers are taken. Japanese lockers don't have restrictions on weight, but there are size restrictions. We cover this in our blog post on coin lockers which you should check out.
Hope this helps!