Google Earth has a number of Settings governing Touring, bubble display etc. Most of them can be set to the GE defaults but changing a few of them make a big difference when you are watching a Tour.

Click "Tools"/"Options to get to the five Tabs:

1) 3D View

I think that the ones I use are the the default settings.

2) Cache

Set your Disk Cache Size to the biggest number you can - in my case it is 2000MB. The larger the cache, the less often Google Earth has to re-load information you've already looked at.

3) Touring

These settings give a fairly good Tour - a reasonable time to move between Placemarks and long enough on each to display a bubble. Remember to select "Show balloon when waiting at features" - sometimes GE seems to reset it.

4) Navigation

These settings give a fairly good Tour.

5) General

Google Earth warns you when selecting "Allow access to local files and personal data". I have it selected because I use Google earth to access files on my computer via clickable links (hence all the "Search this Trip" links). The links won't work on anyone else's computer so you may want to leave this unselected.