Hi MSG
You should not have to fetch as Google to get your pages indexed and please with deference to Paul, above, posting on Google+ will not speed up indexing. If it did then people would be all over it and they are not. You also can only apply to Google news if you have a newsworthy site and I can tell you right now that 90+% of sites are rejected because what they post is not news.
The fact that a page is posted puts it in the sitemap which is picked up by Google. Also depending on the size of your site some of it is crawled by Google every day. Just go to Google Seach Console Crawl Stats to see that.
I have seen pages indexed in under a minute (none news sites - yes seriously) and others take a week. What is of major concern is how you say that these pages are not linked from anywhere because there lies a large part of your problem. You need a proper site structure so that link juice passes from the main menu down through all the pages of your website. The more 'shallow' this is, the better as the pages are closer to the top.
If you are burying pages deep in your website with no logical route to them then they are just not going to rank quickly.
Read more on site architecture here: https://moz.com/blog/site-architecture-for-seo It's old but still very relevant.
You need a solid site structure which starts with the main menu with proper departments, categories and if necessary, sub-categories.
Sort that out and you will see your pages indexed much quicker.
If you can get do-follow backlinks then this will help, but certainly not from Facebook and G+ as they are all nofollow.
Regards
Nigel