I would like to know what is the difference between traveling and travelling. Are both right? Or it just depends on whether you are using American English or British English. Me gustaría saber cuál es el gerundio del verbo "to travel": ¿traveling o travelling?
In his travels, he has visited nineteen countries. and When he is travelling, he feels alive. When travelling, he feels alive. The two "travels" phrases (and also "in my travels") are used to summarize all your travels. That's different than "when I travel", which introduces something that frequently happens during your travelling.
An example of a travelling show is a circus. In such travelling shows, there were frequently folks who made "potions" or 'medicines" said to cure all kinds of diseases.
Here you have an action that began in the past and continues up to the present, which is clearly marked with a time period that includes the present ("for the last six months"). This is an obvious situation for using the present perfect, and I don't think a native speaker would think of using any other tense. If the travelling is now over, then the past tense would be correct, but "for the ...
The use of the present progressive (are travelling/estas viajando) implies that the action is already in progress unless you add an advebial phrase that indicates future action (are travelling to tomorrow, next year). The use of the periphrasis "are going to travel / vas a viajar" always implies future action.
There are two differences: Travelling for days could be by rail or sea, whereas "on the road" is more specific. "A few days" may be more than "a couple of days".