Write Javascript to load markers on to a google map

General information for the website: Landscaping
Num. of web pages/modules: 1
Description of requirements/features: Hello, I require some javascript for my existing website that will produce a google map with a number of maps pins.

I need the script to do the following:

1. Visit a route to grab the list of supplied addresses. The existing route already generates a correctly formated XML output that contains a list of postcodes, the URL will be supplied.
2. Geocode the postcode/s using client side processing or using a service like postcodes.io
3. Once geocoded, grab the lat/long coords and store them back in the database to reduce overheads the next time the page is loaded and time spent geocoding.
4. Generate a marker on the map:
4.1 The marker should be coloured based upon a key that will also come with the XML.
4.2 Every marker should have an info bubble and needs to display some additional content for that marker, the info bubble should also be styled.
4.3 A custom marker icon must be used rather than the google maps default
5. Code must have ability to use a custom map style (snazzymaps)
6. The map must zoom into the area where the pins are located
7. Also provide some code to allow the user to use a "show on map" button that will highlight the pin on the map.
8. Ask the user if they wish to provide their current location and show it as a dot or different coloured marker on the map

Overall, I am looking for a concise piece of javascript that is fast and reliable, it should be capable of dealing with 1000+ rows without falling over. Im also looking for advice to avoid running into issues when geocoding large sets of data. Finally, the code should be easy to read and be well commented.
Extra notes: