As they say where there's a Will there's a way, now assuming we're talking about an independent entity(Kashmir) here I'll give you a solution that may work ~
1) Nepal is also landlocked & even worse when it comes to transportation, comparatively you have better roads/railways on all three sides so this is pretty much a non issue as far as I'm concerned !
2) You don't need an army if everyone(big 3) at the negotiating table signs a peace treaty ratified by the UN, anyone violating that must face sanctions !
3) You have tourism & some of the world's finest orchards not to mention plentiful water resources, that should help you build a strong economy in the long run just like SL/Maldives/Seychelles/Mauritius which also depend on tourism alot !
4) When you have the big 3 on your side do you really think the US will dare put anything for global surveillance over there
If all the 4 parties in question want a solution then really sky is the only limit to what will undoubtedly be the Asian century