You can use the same javascript-object-based syntax as you would in your server-side code:
MasterTrip.find(
{ filter: { include: ['froms', 'tos', 'trips'] } },
function(respoonse) {
// etc.
});
The URL will contain a single query parameter filter
with a JSON representation of the object. If you prefer to keep the URL query expanded, you can use the following code:
MasterTrip.find(
{ 'filter[include]': ['froms', 'tos', 'trips'] },
function(response) {
// etc.
});